Fletching arrows is not all that difficult.

As for the minimum, you will need a jig, clamp and some glue.

Take a look on ebay. There are normally some running ads for Bitzenberger fletching jigs for something like $30 for the jig and a clamp. You will want a straight clamp as opposed to a helical.

Get some vanes, hopefully the same brand your arrows are already fletched with and some glue. Steel force Beyond Bond works very well. That' s about it.

Prep the shaft using a good degreaser that does not leave behind any residue (denatured alcohol or acetone). Clean the bonding surface of the vane (don' t use acetone for this). Put the vane in the clamp, apply the glue to the vane, put the clamp in the jig and press onto the arrow shaft. Repeat for the other fletches.