Yard sales and used furniture stores are your friend. Remember those old green tables they used to have in art class at high school ??They weighed a ton, and are pretty much indestructible... I picked up one left behind by a tenant, laid a sheet of 3/4 ply on top, and I've got one heeck of a 4 x 8 table. I don't do bikes on it, as I added a glass top as well and do sign work on it.
But.... I have 5 or 6 other cheap tables purchased for $10 or less at auctions, antique stores, and flea markets that I do use for workbenches.
Keep your eyes peeled for used truck toolboxes for the big Semi trucks. I have one of them, the front opens downward and it has tons of room inside. I bolted 4 angle iron legs to it and it also is a great workbench.
Where you see the chainsaw sharpener bolted on I also can bolt a vice to it.....With stuff in it it is pretty heavy so it doesn't go anywhere. Only problem is I keep dropping stuff in the gap between the door and the top. I paid $75 for the toolbox, new they are pretty expensive.
Another great source of cheap tables is your local Restore (Habitat for Humanity) They often have complete kitchen lower cabinet sets as well as solid core doors you can use for the top. My shop has two with thin plywood tops and they aren't as sturdy as I would like but they are plenty fine for bikes. Stay away from particleboard and look for older solid wood cabinets. If you do welding stick with metal stuff if you can find any you can afford.
In a pinch even one of those plastic folding tables with the grey/white top will work pretty well as a workbench. Sometimes you can pick used ones with cosmetic damage from rental places.....or like I did , from a company that does yard sales.
