My first router table was just a 2 ft square piece of 3/4 birch plywood with a 2" hole a little off center for the router bit, plus the mounting holes around it to attach a 1 hp fixed base router underneath. For a fence, I had a 2 X 4 that was a little longer than the router table, with the face edge jointed flat and a notch in the middle of it to go around the router bit. Two C clamps held this fence in place and two more C clamps held the table to the edge of my work bench or saw horse. It was portable, very flexible, and was easy to use for most routing chores, but now that I have two REAL router tables, I don't ever want to go back. It was a great and very cheap way to get started, and very easy to make, but the features of a full size router table and fence make them so much easier to use.
If money is tight, go with something like my first DIY router table. If you can afford better, go with one of the many better router tables on the market. Inserts will let you adjust the bit opening to the ideal size, A thin, but strong plate will give you more bit depth adjustment, vacuum attachments will keep your shop and lungs cleaner, micro adjustment of the fence will get you more accuracy, etc. All this makes it easier to get good results. Much can be done with a DIY table like I had, but accuracy will be significantly limited.
Central North Carolina