Will at&t give me a new sim card?

Okay so I have a windows phone for at&t and I have a date plan and everything. I want to buy an iPhone off of eBay but if I do my sim card is too big for the iPhone 4 since it requires a micro sim card and I have a regular one. I don't want to risk cutting it and breaking it, what I want to know is that if I do buy the phone and go to my local at&t store will they supply the micro sim card that I need for the iPhone I bought from eBay because my regular sim card won't fit into the iPhone 4?

Yep, itll cost you like $60 tho.

Of course, you are their customer. They have to service your needs. No one said you HAVE to buy your phone from them. I bought my phone off Ebay and they gave one to me, no problem.
If they do charge you, it will only be $5.95.