Having been a college student, I understand the budget issue.... even though it was 45 years back....
Try looking at thrift shops for a kilt. My neighbor found a USA Kilts casual in American Heritage tartan in my size along with a St Kilda jacobite shirt... for $25 USD.
Check the good quality kilt sites for their clearance sections... I got a 16 oz black shadow tartan kilt (supposedly ex-hire but seemed more like new unsed, not even any kilt pin holes) for 40 GBP and a bunch of piper hose in various colors for 4-5 GBP per pair. Shipping for the whole order was approx. $30 USD.
There are some good deals available, just need chase them down.

Good luck finding your deals!