some tile dealers and even distributors have specials and clearance items. as an example; i just picked up 25 sq ft of 1 1/2"x 1 1/2" tiles that the distributor had out at 90% off. very small tiles like 3/4" x 3/4" might be hard to find, but 1x1 should be in the discount bins.

google: ceramic tile, [your city or county], and maybe mosaic
and see what pops up.

let me add: if you can use them, check around and find a few tilesetters, they always have a lot of cutoffs that they throw away. you might be able to cobble something together from a bunch of scrap.

if it is a reall detailed design, you might just take a hammer to the lot of them and not worry about precise cutting. you could just dig thru them to fit them up.