I like to consider myself a multi-tool collector. For those of us who were collecting cards before the days of the internet your choices for adding cards to your collection were limited to busting wax, buying singles from your LCS (if you had one), trading with fellow collectors, and mail order. All of those options are still valid, but the internet gives us so many more options. Sites like justcommons.com, sportslots.com, eBay, Listia, and COMC offer all sorts of options to not just buy new cards, but to sell as well.
Like I said I consider myself a multi-tool collector, meaning I will use any means available to further my collection. That being said I noticed a very disturbing trend over on COMC on my last Black Friday shopping spree that was echoed around the card collecting blogosphere. Good deals on COMC are becoming much harder to find and in some instances the pricing is getting absurd.
If you don't know the story, COMC parted ways with Beckett over a year ago and has been trying to rebuild it's card catalog using customer help. What that meant was no longer was a Beckett book price listed with the card. Say what you will about Beckett pricing, but at least it put a ceiling on pricing, usually.
If you've been on COMC lately the offer a SRP - Suggested Retail Price, a SLP - Suggested List Price, and a SWP - Suggested Wholesale Price. And for very common cards that have lots of sales on COMC that works OK, but when you start getting into some of the rarer cards, or cards that there are only one of for sale and there is no SRP or SLP, then it starts to get a little crazy. Sure there's a quarter added onto the price for COMC's handling fee, but some sellers really just throwing out some crazy prices. Maybe they expect you to just come back and counter offer to their insanely high price, but for me I just shake my head and move on.
For me the advantage of shopping on COMC is you can peruse a lot of cards and there's just one flat shipping fee, but if I can find a card cheaper elsewhere, I'm going elsewhere. It also hurts that COMC's overhaul of their site still isn't finished and sellers on their site are getting a little impatient, which probably leads to fewer sellers sending in cards to add to their inventory, which means lower overall selection, variety, and competition.
I was going to put up some examples, but I rather you journey over there and explore the issue for yourself and post your findings in the comments.