If you look at the ideas Mike and James posted, both are good.
To start cheap is just buy a bunch of clamps. If you need to stand something on its side to plane edge grain. Clamp a length of 4×4 to the table, then clamp the work piece to the 4×4. If the piece is long, work at the edge of the table and let the piece hang off the side of the table.
Another way to start is make a simple moxon vise and clamp it to your kitchen table. You don’t need expensive clamps either.
If you have a little extra room, the portable bench Mike posted is an awesome way to get started
Just remember where there is a will, there is a way. Be creative and have fun.