For a sporran, rather than something furry take a look in a charity shop for a suitable handbag or if nothing suitable in that section perhaps a slightly scruffy leather jacket to cut up to make a simple spog/circle with folded edges.

To wear over the shirt perhaps a plaid - a long one like a piper or drummer maybe, or a more blanket like one for a laird.
Personally I favour a long plaid, as it is little bother to wear and can be adjusted swiftly to ward of wind, rain or hailstones and the folds under the right arm - worn loosely rather than militarily tight - make a handy place to hide anachronistic items either in the folds or in a shoulder bag concealed beneath it.

If you make a balmoral from woven stuff then you need two discs about 13 or 14 inches diameter - you can always reduce them if you find that is too large, join the outer edges, cut a head shaped hole in one and add a folded over strip of fabric to make a band, thread a ribbon or tape through the fold. You could put a badge or some small decoration - usually worn somewhere above the left temple, with the cap pulled down to the right to show the underside of the ring of fabric.

If cash is limited I'd suggest a single colour kilt and plaid rather then going for a fancier kilt - unless it would be cheaper to buy different pieces to join up. I made a kilt very cheaply from a king size duvet cover, using the fabric doubled so there was a fold or a join rather than a hem at the lower edge. If it is a bit faded all the better - so you don't look as though it is your first time in costume.

Anne the Pleater :ootd: