Hey, starting a business is quite easy. Just put up a website offering what you do--it isn't that expensive to get a template if you do not know how to build--and put yourself out there.
Feel free to look at my site at www.waldorfpc.com
to get some ideas. Do not copy any of it it as it is copyrighted: but, just use it for ideas.
All of the service my business offers can be done from home or done by yourself unless you should want to grow. To get you started, I'd suggest reading www.fonerbooks.com
There is alot of guides here you will find very useful. Not to mention, this site is full of ideas.
If you want to start your business with very little expense, collect the money up front--three quarters of it--and build the machines. Just to be on the safe side, save all your boxes to parts and receipts, and do not spend any of the left over money until the customer is satisfied. This is just in case of a refund request. The last thing you need is a mad customer because you don't have the money to refund the request. This could mean big trouble.
Another important thing I should let you know, have an account with some money set aside. This serves as a cushion on a rainy day.
Don't be fooled by thinking you'll need a merchant account to accept money. There are a plenty of online payment processors you can use that accept credit cards and checks. Paypal is one of them to start with.