Pure ammonia can be difficult to track down but I've heard it's sold at Ace Hardware. I've never used this method as I haven't been able to find the stuff near me. Plus, you have to keep dosing it. When you've got a lot of fish tanks, it can be hard to remember to do stuff like that. I've personally used uncooked shrimp to cycle a lot of my tanks. Just put one in a piece of pantyhose (or a filter media bag which should be available at Petsmart or any fish store and is probably cheaper than pantyhose) and throw it in your tank. As it rots, it will create a constant supply of ammonia. There's really nothing more to it other than to test your water to know how the cycle is progressing.
If I were setting up a new betta tank, this would be my shopping list:
-Test kit - $18 (this is extremely important. You need it to know how the cycle is progressing and is pretty much an essential tool for all fishkeepers. Don't get the paper test strips! They're inaccurate and actually more expensive. This test kit goes for about $30 or more in stores so it's better to buy online):
Freshwater Master Test Kit
-A plain ol' 10g glass tank from Petsmart for about $11 or $12 (5.5g tanks cost about the same, but the bigger the better, so why not a 10g?)
-A filter with an adjustable flow rate like this one ($13):
Whisper In-Tank Filter 10i - 90 gph
-A heater like this one ($17):
Visi-Therm Stealth Heater - 50W - 8 3/4 in. - up to 15 gallon
-Glass canopy ($10):
20" Glass Canopy (Perfecto)
-A strip fluorescent light from Home Depot (~$10)
-Gravel or sand (you can buy a 50lb bag of play sand at Home Depot for like $4 and it looks great...just rinse it really well before you add it to the tank)
-Silk plants (or live plants like java fern and java moss)
-A piece of driftwood or two
-Some pieces of slate from a landscaping store to make some caves (bettas love caves!)
-A net
-A gravel vaccum
-Water conditioner (Tetra Aquasafe or Prime are great)
-Fish food (Hikari Bio-Gold pellets as a staple diet, frozen bloodworms for twice weekly treats)
-Thermometer
That's it, really. The initial setup is somewhat expensive but the long-term upkeep is really, really cheap. A 10g tank would allow you to keep your betta fish along with a shoal of six or so corydoras catfish, which make great tankmates and are really funny little fish. The 10g tank, canopy, filter and lights comes to $45, which is the same price the Eclipse 3 runs for. Plus, the Eclipse filter tends to be pretty strong which can bug bettas.