Etsy would probably be another option, but I've always thought of it as a venue for selling handcrafted items, not so much "vintage" clothing. I could be wrong.
Also, I can expand some more on my eBay expertise to help you get maximum auction visitors. I've been buying and selling on eBay since 1998, so I've learned some ins and outs.
Take lots of well lit photos of each item; front, back, etc. Get close ups of the tags and any imperfections such as tears or holes. You'll want to note those imperfections in the description. You get up to 12 photos per listing, so go crazy.
Listing titles are limited to 80 characters. Use common keywords related to your item, so rather than saying "Poison The Well Hoodie" say something like "Poison The Well Hoodie XL Rare Opposite Of December Era PTW Black Sweatshirt". Try to squeeze as many keywords in the title as possible.
Select the appropriate category. Typically band merch can go in either Music Memorabilia or Men's Clothing. I haven't really seen a difference in listing in one category versus the other.
Select and enter all of the item details. Size, color, type, condition, etc.
Write a detailed item description. Restate the item title, then go into a longer description of the items condition, again, note any imperfections here and tell the potential buyer to review the photos. Also, list any measurements of the item such as chest width (armpit to armpit) and length (highest point of shirt to hemline). Last, note what shipping method you will be using and if the shipping is free.
Pricing. As mentioned in my previous post, this is entirely up to you. You can search past listings to see if a similar item has actually sold and what price it fetched. Start there and price accordingly. Again, you have the options of a several day auction (I recommend 10-days) or use the Buy It Now function with Offer settings if you want to test the waters.
Delivery/shipping methods. Ignore all of the recommended settings here. They are shit. If you are shipping only single shirts or hoodies, use these plastic sealable bags. They add almost no additional weight to the final shipment cost. You can test out the package sizing by folding a shirt, placing it in a shipping bag and measuring it. Enter that (generic) size into the eBay package details. A large t-shirt weighs about 6oz and a large hoodie is about 20oz, give or take. Choose your shipping method, USPS First Class, UPS Ground, etc. This is a personal preference. USPS is likely the cheapest option. A shirt will likely cost a few bucks, but a sweatshirt may set you back $10 depending on the material and size. Calculate this cost into your "Buy It Now" price if you want to. Free shipping attracts more customers, so you should use the "Offer free shipping" method, but you could also just put the shipping at a flat/fixed amount of $3 and call it even. Free or low cost is ideal. International shipping is entirely up to you. I don't deal with shipping beyond the U.S. since it has become such a hassle with customs and larger shipping costs.
That's mostly it. Keep an eye on each auction to see how many "Watchers" you get with each listing as the days pass. You may get questions about items, so be sure to respond right away.
Let me know if you have any specific questions!