Verification ? Is it needed ?

Hi all. So i was wondering something. I have a phone verified Twitter account that twitter never asked me for the sms code i mean they send it once and thats it.
Now i am using an old profile to tweet links every thing was cool but this morning i get to verify my twitter with a Phone Number .
So my question is can i verify it with all ready used number for other account ?
And also i found a place where they sell account ( i am not allowed to post links sorry ) with PVS because i tweet a lot of links will they ask me for SMS code ? I mean the Twitter Profiles are Verified all ready so i think no but i am not sure ?!

I've heard about Google voice number but didn't try yet. As I know you should have Gmail account for each Twitter account.