Alright. I've got a minute, so I'll give a full answer.
1. Pull out all your CDs in poor condition and set them aside in a box. You may be able to sell them as SKUFF cds at Everyday Music or Half-Priced books, but you won't get enough online for them to warrant the time in listing them, and who needs bad reviews from angry customers messing with your potential sales.
2. Look up each remaining CD on Amazon.com, noting the going rate for your condition. (Very Good to Like New. Except for true rarities, anything you'd rate as less by Amazon's rating guide should be going in the step 1 stack).
3. Separate these CDs into stacks by going-rate.
Stack A: $2.50 or less.
Stack B: $3.00 to $5.50.
Stack C: $6.00 - $15.00.
Stack D: $15.00 or more, CDs not found on amazon, CDs found, but with nothing in stock.
4. Put stack A in a box, separate from the step 1 CDs. Ask yourself if you have the time or need the money that badly. You don't. Time is money and Amazon takes a cut of your nothing. Take stack A down to a used record/book store SEPARATE from the SKUFF stack (step 1). Otherwise, some stores will take a quick glance, see a bunch of broken CDs and give you a dirt cheap estimate or say no entirely. Try unloading the stack from step 1 on a separate trip, or just "suddenly remember' after they've looked at stack A and paid for them, that you've got another stack in the car.
5. Take stack D ($15.00 or more) and do a completed listings search on Ebay to determine the going rate of each CD. If it's more on Ebay, do a little googling on the rarity, demand and Out-Of-Print status, then go ahead and list it on Ebay with that knowledge, making sure to sell it internationally. If it's not listed on Ebay or Amazon, do a little more googling to determine if it's ultra-rare and in demand or ultra-no-one-gives-a-crap and no-one's ever heard of it. Ultra Rare? Sell it on Ebay at an exorbitant price. Ultra no-one-gives-a-crap? Sell it on Amazon at an exorbitant price. There's no listing fees and it can stay up there for eternity until someone who cares pays for it.
6. Count the remaining stack D CDs from step 5, the ones that sold for more or equal on Amazon. Add that to the count for stacks B and C.
Does the count reach over 100?
Yes: Get month-long Pro Subscription to Amazon.com.
No: Drop stack B off where-ever you sold stack A and the SKUFFs.
7. All remaining CDs: Set aside a day and make sure to list them all on Amazon at once. Time is money, and you want to avoid as many petty trips to the post office as possible by selling as much as you can at the same time. (Same goes for your ebay sales here. Ebay's even better for saving post office trips, since you can schedule an end-date for all the auctions).
AMAZON SHIPPING TIPS (cut-and-pasted from my response to soundslikepuget, since I'm sick of writing):
The shipping you offer should depend on "weight and what you're mailing it in. If you buy bubble-wrap CD mailers in bulk (officemax) and you're only selling single CDs, you may break out about even on international shipping or occasionally gain a buck. With media such as CDs, it's also cheaper to send First Class domestically instead of media mail, since the CD is usually less than 5 ounces and First Class is a lower price at this rate. You only want to go media mail when sending more than one CD or heavier media items in a package.
When selling low-priced, low-weight media on Amazon, I'd recommend offering Standard and International only (since it's true that their Expedited shipping compensation is often unfair), and offering Expedited shipping only on CDs priced over $10. The Expedited option might make the difference in selling that rare $80.00 CD when that rich last-minute buyer has procrastinated on getting a birthday present for their wife/boyfriend/daughter, ect."