(Sorry, I made a grammatical error on my first post's title)

I'm thinking of getting a newer cellphone through a Yahoo auction. Since I'm new to Yahoo Auctions, does anyone have any advice to help me or things I need to be wary of through the purchasing process? I'm pretty eBay savvy, so I know when a deal is too cheap for a reason or to check the seller's feedback.

I have done a little bit of research on the matter. This post will be helpful when I'm done. Also, I've been double-checking the IMEI posted on Docomo's Network Restriction webapp (Pretty much avoiding anything that isn't a 〇 in case I want to get the phone unlocked in the future). I've also checked with my MVNO, B-Mobile, to make sure it will work, but I'll either have to cut my current SIM or order a new one.

FOLLOW-UP: Figured I might share my experience in case it helps...
Had to register my account by text message reply before I could bid on anything.
Even if you set your default email to a gmail account (e.g.), you will not receive notifications about your auctions... Which leads me to the next thing.
I tried being a good customer by paying immediately after the auction ended, but I didn't go back to the auction page to hit a required "Payment sent" notification button.
36 hours later after not getting anything in my Gmail about the auction, I checked my Yahoo email to find out that I was completely burned... one email from the user saying "Thanks you for your bid, please pay and confirm your address in 24 hours. Please call me at (phone number)", another from the following morning saying "Thanks for the payment, please confirm your address", then a final one from the night before saying "It is assumed that you don't want to buy this. Cancelling the auction". Both my bid AND the auction was cancelled and I received negative feedback. I called the guy immediately, a bit mad, but I played the innocently confused card wondering what was going on. After talking to the guy a bit, he understood that this was my first time (and that I live in Japan) and was a bit apologetic.

That night, I got another detailed email from him directly to my Gmail with complete instructions on how to resolve the auction. Since the payment was already in the Japan NetBank account, I just had to hit a button and give him my address. Two days later, I got my new phone and since he was from Shizuoka Prefecture, he included a box of inagi pies as well (the souvenir speciality of the area). While I don't think I can reverse the negative feedback, he did post a follow-up comment to it saying "Sorry, he's a good buyer!"