Custom Bumper Stickers

My friend and I want to go into business together to make custom stickers for people. For example, someone sends us what they want on it and we get there. We know all the necessary hardware, and we are eager to begin.

The only thing is that we do not really know how to begin. How can we be known? How should we advertise? Will we need a kind of license or permit to sell? Is there anything else we should know?

All advice is appreciated!

For a company like this, the volume is the only way to make a profit. Custom work is by its nature, volume low.
While you wait for those who are committed clients who are willing to pay big money for stickers vanity, you need to look at some jobs and reproducible steady flow to pay your wages.
However, to sell to the public, you must charge sales tax. Go to the State Comptroller on your state website and see what their requirements are.
The first thing is to develop a website that talks about your ability to custom samples show and gives people a way to design and order their own. No matter what other marketing you do, a point of driving people to the website.
Regarding marketing, talk to booster clubs at local schools, all levels, and see if they contract with you to make their stickers and then they can sell them for you. If their sports teams get playoff, and you can get them out fast enough, you may be able to obtain orders per week until the season is over. (This would be a low margin part of the company, because the boosters will be selling these for profit for the teams.)
Talk to small to medium sized local companies about providing our customers with regular stickers. (In their turn, could offer their customers a small discount for services in exchange for displaying their stickers. Car washes, nail salons, etc.)
Talk to local radio stations, the types who do contests and promotions to see if you can provide stickers that could be incorporated in their struggles. ("I listen to Ray in the morning ...")
Talk to the local Chamber of Commerce about getting a list of other new businesses that could be open to the lowest cost marketing.
Contact the local conventions and a list of upcoming conventions and trade shows. Contact planners and see if you can provide personalized stickers for their events.
Contact local event planners and ask if your stickers could be incorporated in local charitable activities, ("Ball Geezers fundraising in 2009.")
Talk to local concert halls and clubs about produce stickers for upcoming shows.
If you have local successes, talk to local television morning shows about getting their new product segments. You have samples made with the hosts name or the name of the show, plus some other drawings that show civic pride or school. You will need to have more talking points memorized and ready, because the amount of time you have to talk in these segments can be as short as 60 seconds. The most important thing is to get people to your website.
Go to the library and get a list of all magazines that are aimed at hobby - sports, crafts, nature, gardening, cooking, art, anything. Send a press release to their publishers with a new product sample or two of your work, preferably a suitable sample, for hobby and / or a magazine or a publisher ("I think Jane should Cooks Anonymus get a raise. ") (There are hundreds of these magazines be.) With monitoring and luck, you can get published as part of their editorial coverage (which is free for you.) Again, the goal is to get people to your website and that should provide the customer outside your local market.
Keep a record of all the media attention and you get samples.