You can probably buy an inexpensive sporran and kilt belt for less than you can make them.

Casual sporrans (from $15.95 to $35.00) here:
http://stores.channeladvisor.com/Sti...ries/Sporrans/

Semi-formal kilt belt ($22.50) here:
http://stores.channeladvisor.com/Sti.../Kilt%20Belts/

Casual kilt belt ($35) here:
http://www.amerikilt.com/