Some things are right and some things are wrong in this thread.
The best way to start out as a rep is to talk to one and ask about any areas they have that are more difficult for them to reach and ask if you can potentially sub rep for that area. You will likely be paid in gear and do more work than you would like.
The thing about paying for samples and so forth ENTIRELY depends on the company. Some companies even salary their reps. Many reps are paid to go to trade shows and demos. Ones that are not are usually small/new companies.
Also, you do not just become a ski rep. You get a ski brand, a pole brand, a boot company, an outerwear company, an electronics company, a sunglass company and so forth. You have multiple brands and multiple incomes.
I know a fellow who makes a good enough living with 686, capita, and world industries. I know another who is a rep for Fisher, Contour, Cloudveil, and suncloud. I know another who does RVCA, and a few of the Quiksilver subsidiaries.
Transistion into sales rep =
Work in a shop and make friends -> ask to sub rep and become familiar with accounts -> become a sales rep for a small company that is unrelated to your sub rep position and gain more accounts -> wait for the rep you are subrepping to quit or attempt to acquire more unrelated companies to continue to build your accounts -> gain a major account
www.malakye.com lists all the open sales rep positions and sometime offers sub rep positions as well.