What kind of filter should I get for a 5 gallon tank with a betta in it?

I bought a 5 gallon tank and I'm going to get a betta, I know I shouldn't get too powerful of a filter for it so what should I look for when buying one? I was going to get a Microclean 304 Internal Mini Filter, but I'm not sure. I'm also going to get a 25 watt heater (maybe Aquarium Systems Visi-Therm 25 watt, but I read about it getting stuck "on") and an air pump, probably a Tetra Whisper 10. Also, what kind of light is good? I won't have live plants in there, and I heard that a pink light won't strip colour from the fish but I can't find any pink ones. I need a 15 watt light. And that's it for the technical stuff. Any tips?