Yes, your process is almost complete. However, on #6, you do not just "purchase hosting". You either host it on your reseller account or you sign them up under your affiliate hosting account so that you receive an additional $100-$150.
Now, back to your original point. I do not recall the OP of the idea mentioning how much he charges. In fact, I think he does it for free... which I could not afford to do.
I think setting a MSRP of $1,500 but offering websites for $399, signing up as a hosting account and then being done with everything would be the ideal approach. You would need them to signup and give you access to the account or if it is a trusted relationship, you may be able to work out some other payment method.
I hope it works and with you being 15 (which is 3 years under the age requirement on here), you have a huge advantage. I'm a few years older than you but wished that I would have caught on much earlier.
Don't be a stranger. Come back often, contribute and share. There is a new star born every day.