Hi Bee
Do you mean money or time?
In terms of time - I bought the bike almost a year to the day planning on getting the bike on the road last summer. I spent far too much time messing around and not making decisions, the biggest one on whether to split the engine cases and do the full works. In the end, I did. I wish I had made that decision immediately. With the benefit of hindsight, I would recommend just tearing everything down and doing it right. Do it right, do it once. I should have the bike on the road by end of June. That's the plan.
In terms of costs - I would assume a shopping list to get started including:
Primary chains and tensioner
Crank case and conrod bearings (you won't know immediately what colour codes you need by you need 10 crank case and 8 conrod - the colours are irrelevant to price). There is plenty of good advice on this site on bearings and wear - and get familiar with plastigauge.
Hondabond or equivalent (I have Three Bond)
4x Rings kits
Cam Chain replacement kit (chain, tensioner, guide, etc)
Seal kit
Gasket set (if it doesn't include O'rings and oil seals you will need to get those too)
Do the engine right and you can can make decisions on everything else - use, restore or replace. For example, my front shocks were usable as they were but I made the decision to replace the tubes, install progressive springs, and keep the original lowers and polish them, new seals and new copper washers of course. Depends what you want to do. I would heartily recommend rebuilding brake calipers and master cylinders, even if they appear to work. If you don't know the history, do the work. And don't cheap out on the frame - get everything that is supposed to be shiny and black powder coated. I toyed with the idea of painting myself (more time wasted on that). Glad I didn't. Get the engine and frame parts perfect - spend what you need to spend and don't cut corners - the remainder you can make a decision on. I made the assumption that the electrics could fail at any time so are to be replaced, but that's a personal thing (I have had too many bikes with moody electrics in the past). I assume all rubber parts are perished or close to perishing so need replaced too.
If you don't already have one, invest in a good quality bench grinder. Set yourself up with mops and compounds for stainless steel and aluminium. There are loads of great youtube videos on polishing metals and I spent many hours absorbing information and experimenting with the grinder. I will do all my aluminium parts myself and there are plenty of steel fixings been done and still to do too. I have experimented with lots of different paints and the best I have found in VHT engine enamel. It comes in lots of colours and, if you follow instructions, gives great results out a can. If you are tearing down the engine then it is worth giving it some fresh paint (if it needs it). Some parts might be too far gone to polish so a good paint job is essential. You might try a bit of both - I have attached a pic I posted recently where I polished the outside of my front hub but the inner part was too far gone and got painted instead. It actually looks very good and I'm glad I did it that way.
There are lots of costs you don't really expect - specialist tools for example. Honda like their bearing retainer rings and my F1 has three different types, each requiring a specialist tool. I was lucky to get all three for £33 (about $50). If you don't have a well stocked garage, expect to pick up tools as you go.
I love that people on this site pick bikes up for under $500 but in the UK I think SOHC4 bikes are much less common. Finding something worth restoring under £1000 ($1500) is difficult. I paid the bottom of the scale at £900 for mine. I think the finished project total will be £2700 with purchase price, parts, powder coating, tools, paint, polishing, sanding and sundries. I am not that far off that now and I still haven't decided if I am to paint the tank myself or get it done professionally. I want the work to be of a very high standard. Going back to what I was saying and making a decision early on tearing the bike down. There are things you might compromise on, there are things you definitely shouldn't. One compromise I am happy to make is standard nuts and bolts. An old Honda will have loads of M6 nuts, washers and bolts in the 12 / 16 / 20 / 25mm range. I got a pile of stainless steel M6 nuts bolts and washers for not much money. Throw in some stainless M8 and M10 nuts (hex and flange), washer and spring washers too. They will last better than the original Honda stuff and for a fraction of the price. And you will have plenty left over for the next project. I decided to replace all the bolts on the top of the crank case, the ones that show, but decided to clean and polish the ones underneath. Standard replacement stuff and getting full use of your bench grinder can save a fortune on fixings. If you are lucky to live in part of the world where rust is not a problem then you can ignore all that. In the UK, Scotland in particular, it is a problem.
My CB750 had not moved for 26yrs but was a low mileage bike when it was put into storage. The engine was free and there were nice bonus items such as aluminium rims and spokes that could be restored, and an aftermarket Motad exhaust that was in very good condition. Brakes were shot, carbs gummed and tank full of varnish. However, once the carbs were cleaned, oil changed, points set, she fired right up. I think I was lucky. I thought at that point it was going to be easy. Whatever you think it might take in time and money - it will be more. If there is anything on the shopping list above you want to remove, you better have a damn good reason. If you are lucky enough to have bought a bike of known history then you might get away with doing certain jobs.
I don't know if you wanted all that but that's my 2c worth. Tear it down, do the engine right, do the frame parts right, rebuilt the brakes for safety, replace bushings and bearings on wheels / steering / swing arm, replace everything rubber, buy a bench grinder and learn how to use it. It is easy enough to price all this up, and anything else that is obviously needing done on your particular machine. You can then add in a healthy contingency fund for all the stuff you haven't thought of. Hope that helps!