Pet stores are certainly best. You can ask them for a female betta. But if you want to go some place OTHER than a pet store, there are some good Web sites. www.aquabid.com sells some nice fish. www.BettySplendens.com sells show quality fish. Both websites will ship to your location. The fish do well in transit. I've had thousands shipped IN and OUT.
You mean betta fish, right? Betta fish cna lay eggs if you have two of the opposite gender in the same tank. If you have a male and female betta in one tank, they won't fight. If you have two females or two males, they will fight. So, you could see if they get allong. ig the bettas do lay eggs, they can still live together, but you MUST place tyhe eggs in a seperate tank, or they'll most likely be eatten. As for the lifecycle of a betta fish, if properly cared for, they can live for years. Two years is very old for some fish, but one man had a goldfish for 13 years!
Beta fish are solitary fish and generally will attack/annoy any other fish until they are dead. Check with your local pet shop that sell fish to inquire about what, if any, fish can co-exist with Beta. it all depends on how aggressive you betta fish is, i own two male bettas, i placed my first one in the tank with 3 other goldfishes and they get along fine, however when i replaced the 1st betta with the 2nd one, it was the more aggressive one and attacked my other fishes...... my suggestions is to buy a seperator for the betta and have it get use to the other fishes for the first couple of weeks then place them together. just a heads up, doing this can cause a betta to get stressed out, so be on a look out for simptosn of ick hello!
If you have a 10 gallon tank for example, you can have your betta with a school of neon tetras, or rasboras, white cloud minnows, or even ghost shrimp. Just remember that every betta is different as far as temperament, so sometimes it's better to add your betta to the tank when you already have the schooling fish in there, and give everyone a place to hide or chill out to try & avoid the betta being territorial.
If you place a female betta where she can see a male, you'll notice that she will get a large bump on her abdomen (right under her gills.) These are eggs that she will normally release on her own. Most females produce eggs on a regular basis, but if they're next to a male, they produce more. I wouldn't recommend breeding bettas though, unless you do a ton of research first, (if you just throw them together, one will typically kill or horribly injure the other.)I would also not recommend leaving the female near a male as she can become egg bound and potentially die.
It is possible to have two betta in an aquarium for a short while but you would need at least a 6 foot tank with heaps of water plants and other places like rock formations (hidey holes). The reason for this is to avoid them seeing one each other and a place for the victim to retreat to. Eventually they will meet and there will be fighting if you have two males, or flashing followed by nest building and spawning if you have a pair. Once the breeding is over the female will be fleeing.