Ebay/Craigslist arbitrage can work well. You find an item for sale on CL like a nice guitar or what not, check to see what they are selling for on eBay. If there is profit to be made you can call him and tell him you are super interested but are out of state (because you may not find a great item local).
Tell him if he can ship it, you'll send him the cash plus shipping fees. If he agrees tell him you want to pay by paypal for your protection. If he doesn't have an account he can set one up in two minutes.
Tell him it will take a few days for you to load the cash into your paypal account but will definitely 100% buy it if he can wait 72 hours (most people will agree). Get the guitar up on eBay with pictures and description pulled from his CL add and put it on a 3 day auction.
Sell it for a profit, get paid by paypal from the buyer, send the guitar guy the money and the ebay buyers shipping info, get a tracking number done deal.
Due this with multiple items and you can make $300-$500 in 3 days. If you think it doesn't work, talk to my friend Jay, he makes $300-$400 a day doing this full time. There are tons of collector items on CL for pennies on the dollar, it's like a virtual garage sale, and 8 out of 10 posters are using CL because it is free and they have no idea how to use eBay.
Even better is when you find stuff local. Call them, tell them you are out of town and will definitely come pick it up when you return a few days later. Even offer them an extra $10 to hold it if the profit potential is high enough. List it, sell it, go pick it up and ship it.