What is the best bang for buck budget AI coding?

Hi. Poor developer here.

I'm trying to learn AI coding (already have multiple years experience with "normal" programming in various languages.) I want to know how to make my budget (about $30/month) go furthest.

At the moment, I am using:

Z.ai $6/month plan:

Ok model (GLM 4.7) It seems to rate limit/throttle aggressively if I use it a lot.

and

Github copilot $10/month plan:

Seems to reduce model context to 100k tokens, and only offers unlimited access to smaller model (GPT5-mini, Grok Code Fast 1 etc). These models are ok for making precise edits to specific code, but they seem to get stuck when the program is large and has a lot of concurrency etc.

I also have free plans for web/mobile-chat for every model I can find.

I only have older computers, so editors like Cursor or Antigravity are too slow to be usable. So I prefer something that can work with a CLI (opencode preferably).

Do I already have the best deal? Or is there something I am missing. When I try to compare plans, it is confusing and they are not often clear about actual usage limits.

Are Codex or Claude even options at this price point if I want to code for multiple hours per day?