To start selling cPanel you would want either a master reseller, to start selling WHM and end-user cPanel accounts.
If you want a bit more performance and have a slightly higher budget, you might consider a VPS for around $20 or so, plus the $15 per month license of cPanel.
If you are ready for more, you want to get a multi-processor / multi-core server with 4+ GB RAM (8+ GB even better) and start selling VPS using openvz and hypervm.
Also your billing system would be $13 - $16 per month (WHMCS).
Thats the jist of it cost-wise.
You much better off if you know linux. And good to have a natural talent in troubleshooting / logical thinking.