Does T-Mobile charge an activation fee for byod(bring your own device)??


Ive never had a tmobile account with them but i have an AT&T phone i would like to use with them.My question is do they charge an activation fee,ive heard in the past its around $35 but im not sure if they're still doing the activation fee thing,i hear its been gotten rid of and others say no its still there. Anyone know??and will i need to buy a sim card from them,how much are those??i heard around $10 and others say you need to buy the sim card and pay to activate the sim as well,what can you guys tell me about both my questions??sorry for long post.
I was charged 10 dollars per sim plus a 100 deposit
The $10 SIM charge is normal, tho it's sometimes waived. (It was, for me, last time.) The deposit only happens with post-paid accounts and is usually because they either don't like your credit history or because you have none. IIUC: They refund the security deposit after a few months in good standing?