Well, see if there is someone on this forum that is close to your area, and find a filter (or pump with sponge and tubing) for really cheap! :) Otherwise a snail would work, or yes the use of live plants will definitely help with the fact you lack a pump AND makes the tank more... pretty.
Hm? Which part was that referring to? :p I find live plants liven up a tank really easy. And plus there are a good number of people on here who are willing to help out others especially if they are in the same area.
ADF's are surface breathers and get personal like bettas do after a few feedings. They are cute and pretty much blind. They are difficult to feed tho IME because your betta will be a piggy and try and steal its food. Lol.