Actually tiger barbs are one of the more easily bred egg layers (which are harder than livebearers). With any egglayers, getting the first food right is the critical point; you have to think about and arrange for that
before you try and spawn the fish.
I don't know off hand any online sites that would sell you a particular sex of barb; you'll need to learn to sex them yourself and pick out the ones you want from the dealers tanks.
Information on breeding the more common egglayers is freely available online (I think there's a sticky about it on this forum too, if anyone can post it)
If you do decide to breed your tiger barbs, can I please, please
beg you to make sure they're properly marked ones? The quality of tigers has dropped terribly in the last few years, due to indiscriminate breeding and crossing with the green variety, so nearly all the tigers I see now are badly marked by black blotches between the third and fourth stripe