So this is what my suggies eat:
pure fresh sliced veggies, a little bit of lowfat plain yogurt, dry food w/ mealworms etc

I want to know if I really need to buy the other foods from websites I keep seeing here like BLM or OHPW, Need advice! XD

I would suggest getting on a diet that is considered healthy for gliders.
I use dry food. HAPPY GLIDER cereal. but i wouldn't use the dry food from petstore.
the dry food is only a side dish, left in a bowl for about 3 days then thrown out. I also put bag in the freezer, I read here it can develop mold or something at room temperature over time.

You need a fresh staple food to be given everyday.
Staple food like BML, HPW, Pricilla Price diet, etc..
with daily dose of fruits and veggies of course.
I feed mine their daily diet with occasional dry food and treats.