im just going to say your instructions seem misguided and running a filter on water for 24 hours will do little to nothing until your tank CYCLES
if you dont know what that is, please read some threads on this website about fishless cycling or google.com type in fishless cycle
yes, this will take a few weeks and you cant add a fish right away (bummer) but in the long run of your fishes health, it will be happier, healthier and live a longer life. please consider a fishless cycle.
in my honest opinion, paying $47 for a 2.5 gallon fish tank is a rip-off.
if you check craigslist.com you can usually find complete tank setups that people are selling, (or even sometimes giving away free!) from about $10 and up and $50 could have gotten you a decent size tank. yes it would have been used, but i think personally that it would have been a better deal. ( if you took your time looking and kept your eyes open on craigslist)
i suggest a small heater and thermometer.
im pretty sure the bettas you buy dont come from the rice patties and are bred somewhere, so they know no better of fluctuating water conditions.(im unsure of that) could you get away with no heater, not cycling the tank, even putting a betta in one of those smaller bowls? im sure you can, but i highly doubt your fish will be happy, healthy and live a long life. its like shoving you in a refridgerator box and you cannot leave. you must breathe in there, sleep in there, pee in there, poop in there ( and your still breathing in there ) if you get my point...
a general rule of thumb for keeping freshwater fish is 1 inch of the max size the fish will grow per 1 gallon of water. ( ofcourse there are exceptions of some fish needing more .. )
as for glowlight fish they are brightly colored and may attract the attention of the betta, causing them to be killed, especially in an aquarium as small as 2.5 gallons, id recommend against it.