If you search this forum, there is a detailed tutorial on making your own out of .32 short colt brass. Last batch I bought (last year) was $17 / 100 for new Winchester, you drill a two stepped hole, pop in some .27 Hilti or Ramset (green / low power) cartridges from Rona or Home Depot, and a .311 ball to top it off (with a light coat of lube, I use Lee Liquid Alox / Allox?) and hey presto! .32 Rimfire, reloadable.
rustywood.ca has cheap ball, I'm sure some other forum regulars here could cast you some or point you to a supply close to where you may be. Shipping is the worst part of buying things made of lead.
If you don't want to make them, I'll eventually put one of my kids to work making more for me, but they have huge financial ambitions and distorted ideas of the value of their labor. From preliminary discussions, I think mine are going to be priced at a point that will make you want to build your own.
Factory rounds: You could get lucky and find some at a garage or estate sale. They get bought instantly at gun shows. I think there are some advertised on the EE from time to time, expect to pay over $120 a box.