Sorry you can't get a test kit. It's rather important when cycling a tank that size. Can you get test strips? Failing that, in the interest of fish safety, you'd want to perform a 50% water change every other or third day. This is where Prime is so important. It detoxifies ammonia for a couple of days. It would be nice to know your pH. Further advice would be better with this information.
Your going to have a difficult time growing plants in that tank. I don't see provisions for a light. Anubias is a great low-light, hard-to-kill plant that looks nice and fish like. Java fern is also good. Java moss or mossballs. Anything else is going to want light. You could easily use a desk-lamp with that setup.
The Hydor Theo adjustable heater is exactly what you want.