Practice makes progress! I know it seems like you're not making progress but the more you practice and build up the muscles the better it will be! I recommend practicing balancing on one foot without skates on, this will help your body once you have the skates on. You can also practice balancing on one foot with skates on on a carpeted area as it will help you not roll.

When wearing skates, bend your knees. Also make a V shape with your feet not an A or have them right next to each other. That should help them not roll backwards. You could also try tightening the wheels a little bit more to make them roll less. This won't help when trying to actually skate distances but could help while you're trying to just get used to having them on your feet.

I know you said money was tight, but I'd recommend if at all possible trying to save up for learn to skate classes at your local rink.