What are my options to carrier unlock an iPhone 4s I bought off of eBay?

I recently purchased an iPhone 4s off of eBay and it's still carrier locked. Is there a cheap/free way to carrier unlock it? It's currently jailbroken and it used to be on AT&T. I plan on switching it to MetroPCS. I only have the MetroPCS SIM card and it says I have signal but I can't make calls, texts, use the web. I am not a AT&T customer and have no way of becoming one. I really need help. Any suggestions?

There's no way to get a carrier unlock. Only AT&T can do that and they will only do it for the customer who had the contract for it and even then, not until the contract was over and paid in full.

I got same situation with AT&T Iphone, i was look every where to unlock this Iphone, and what i found out it cost now around $100., from oktober Apple change law and dont believe if you find info. On internet what sombody can unlock your Iphone for $20, its all spam, what i did i order Geavey sim card you can find on Ebay or Amazon its price around $10., my frend give me advise, he unlock his Iphone 4 like that for T Mobile carier about 1-months ago, so you can try ✌️