RAF is a two edged sword. You can level up WAY faster, as you not only get triple kill experience, but triple quest experience. Where it cuts the other way is the fact that you level up WAY faster, earning a lot less gold along the way.

If you don't have a higher level toon feeding your group, you'll be gold starved. If that's the case, only buy the level up skills that you need and can use, skipping learning anything not needed. Don't buy anything at the auction house. With a group of two you won't likely need it, and with more you for sure won't need it. Quest junk will do for gear. Loot everything you can (this WILL slow you down), and sell it. You "may" want to take skinning, to earn a little bit of gold along the way. Mining and Herbs take too much time away from leveling. Avoid any trade skill, like enchanting, blacksmithing, or whatever. They are a gold sink.

If you DO have a higher level toon feeding your group, then I'd still avoid the Auction House, but you can at least level your learned skills. I'd skip looting anything outside of instances. You'll miss a few green drops, but it just slows you down. I wouldn't bother with any professions until you get to a higher level (60, 70, 80, your choice). It slows you down, and the whole point of multi-box RAF is fast leveling. However, if you have the cash for it. do whatever trips your trigger.

If I don't have a healer in my group, I'll usually learn first aid on my tank or main character, but if you're gold starved, the cloth sells decent on the auction house.

If you spend very carefully, you can probably get by spending about one thousand gold per character, including fast ground mount by level sixty. Mostly I run nearly double that, and I never buy gear, bank slots, or anything not needed. I don't even repair gear, as I level though it so fast that I never wear it out.

Whether you instance boost, or quest, you should be able to make level one to sixty for your grouped toons in less than two days played if you don't get distracted with professions, PVP, dueling, or whatever. Good luck, and have fun 8o