You may want to get a hepa filer/air purifier for your room or make sure you have good air circulation even with PLA.
Also, depending on the printer you may want to consider getting an enclosure or building one to limit the noise it generates.
If you have room mates be sure to consult with them, as the noise can get annoying especially at night.
In terms of the business, you may want to consider registering your business so that you can issue invoices. Depending on your region, you may not need to register your business to issue invoices. Read up on your local business regulations/rules (taxes, etc…). If you are able to issue invoices, 3D Hubs takes a 12.5% commission, otherwise, you are charged VAT (~3%).
For financing your printer, it might be worth getting a silent business partner to lend you the capital in exchange for a % share in the business profits.
This way you can buy out their share if the business is doing good, and you don’t loose as much money if the business tanks. Be sure you clearly communicate with your business partner if you choose to do this, and have the agreement on paper and be sure to maintain majority ownership.