Ebay has millions of buyers--that's what you pay for. IMO it is worth the fee. TST has dozens, at best. Craigslist is good if your stuff is good, but again a limited audience.
Retailers like Second Swing, Quickshipgolf, 3Balls, GlobalGolf (same inventory as 3Balls) and the Callaway Preowned shop are all excellent places to buy. Look for their listings on eBay, since they often ask for Best Offers, where their website prices are firm.
Today, you have to be a savvy buyer on eBay. Know exactly what you want and what it looks like, right down to the manufacturer's logo and colors.That is why online retailers like those above are best, because they are authorized dealers and get their inventory mostly from the manufacturers themselves.
When you sell on eBay, you have to know the rules, your rights, be honest and professional at all times. Take excellent photos (no fuzzy ones) from all angles. Create the ad that you would want to see. Mark up all your prices by 20% then let the buyer talk you down (no need to even at Best Offer to your listing, since all messages give buyers and opportunity to send you an offer).
Also, as others have said, package your sold items well. The USPS is your enemy. Know their insurance policy, as well.
NOTE: Be careful about talking about your eBay business or any other commercial enterprise of yours on these boards. They are very strict about no soliciting or even mentioning of your business.