A few years back our Doggy daycare had a "prom" I got Spot a bowtie at a local costume shop.

Sometimes human clothes can be adapted for the dogs, and if you find things on sale or clearance it can be cheaper too! I have used chidlren's clothes that I purchased cheap at Target...shirts (football jersey's) or for the girls, dance skirts. Boxer shorts can be used, if you use the hole for the tail...