Can I unlock a Verizon iphone 4 to work for T-mobile?

So i want to buy a iphone 4 on ebay but all of the phones that seem to be a reasonable price are all locked. I was wondering if i could buy a iphone that is meant to be for Version and unlock it. I was also wondering if I can unlock it before activation it to T-mobile? If it is possible, how do i unlock it?

If you look on bidding sites such as eBay they have listings of iPhones which are unlocked meaning they can be used for any carrier that uses a sim card. If you buy a phone that isn't unlocked already you can pay to have someone do it for you but it can be quite expensive.

Verizon iPhone 4 can't be unlocked as they don't have SIM slots. You can buy unlocked iPhone 4 or AT&T iPhone 4 and get it unlocked and use on T-Mobile. Don't buy any iPhone 4 that's locked to Verizon or Sprint or C-Spire. If you need iPhone 4 unlocked cheaper, mail me for references.

Nope. Verizon is a CDMA network, T-Mobile is GSM. Also the iPhone 4 was either GSM or CDMA, can't switch between the 2.