Some plans are out there to make your own lift tables using angle iron or even wood...
The question becomes how strong does it need to be? The price of wood has gone up so much the wooden designs are too costly.
Bedframes can supply decent angle iron to defeat the costs if you have access to them cheaply.
You can buy steel diamond plate for the tabletop surface. The advantage of building your own quickly becomes a mute point if a used HF lift can do the job for you for less. Depends really as to what you value more, your limited time or if you have the cash to spend.
If you are t working, then sometimes you have the time but not the money.