If you want to start with a zero-budget approach and build from there, I would start with bcoin: https://bcoin.io/guides.html

You can install it and run it as a bitcoin full node, and set it to CPU mining mode. Then you can play with the mempool, etc.

This is extremely unlikely to find a block, but it's a great way to get started without spending any money (assuming you already have a computer with enough storage space to support a full node).

Now, this is how I would approach it if you are at all comfortable with coding or or have an interest in it... if you don't know how to code and don't want to learn... then you will probably end up spending money and losing money...