I will address the countertop idea. I would cut the counter top to the size you are wanting. when cutting this, if you are using a jig saw or sabre saw, make sure you ask for reverse cutting blades. These will not damage the formica top surface.
Now, I am assuming that the counter tops that you have are made from particle board with formica covering the tops and sides.
If this is the case then:
Go to the hardware store and get the screw on legs, the lenght that you are wanting. These legs should have a machined screw on the opposite end of the leg that hits the floor.
Then ask for the leg plates that screw to the table underneath section. you will want four of these per table or one per leg.
now, screw these leg adapters into the ends of each table, noting that the adapters are on an angle. The angle is so that the legs will protrude out and over the sides of the table for more stability.
Attached the plates appropriately. Then screw the legs into the plates and walla, you have an instant table.
Now to dress off the bitter ends of the counter top, you can either buy the counter top ends or insert a board on the ends and glue on ceramic tile bull nose's on the ends. Ask for ceramic tile bull nose. See what you think
If you are on a tight budget, forge the tile.
Otherwise your legs and attachments should run about $12 per set of four.