A really low budget. I'm a college student just lookin for a hobby. I don't have a co2 system but I do have a air wall along the back if the tank to try an help. Not sure how good that is doing. I do have a t5 lighting with the white and pink lighting. The plants I have in there now are growing rapidly. Not to sure which ones they are tho. I am open to suggestions as I am trying to learn and get better.
A bubbler won't help with CO2, it just creates surface agitation which off-gases CO2 and allows for oxygen exchange.
It may help if you post a photo of your tank.
Do you have any fish/shrimp/snails living in the tank currently?
Swapping substrate on an existing tank can result in ammonia spikes and even repeat cycles.
There are all kinds of cheap substrates but which get suggested will depend upon on several factors. You'll need to research each one here on the forum in order to make a more informed decision.
Safe T Sorb is about $5 for 40lbs. It will temporarily alter water parameters if this is an already established tank. You can have it shipped to you (total cost) for under $10. It's got a high CEC (ability to absorb nutrients and slowly release them over time).
Pool Filter Sand comes in a variety of sizes and colors. Usually $2-$5 for 50lbs.
Black blasting grit is cheap
Crushed lava rock is cheap
Flourite is usually about $15-$20 per bag and comes in a few different colors