This is the place where Stones fans can advertise anything for sale, wanted, trade or whatever, from fan to fan. Advertisements are for free. To see the old ads go here.
You don't actually 'convert' rar files, you 'open' them, I think of them as an envelope or parcel which contains stuff.
The most common freeware app is winrar, you d/l a 30 day 'trial' version but it still works after 30 days but with a little 'nag' box suggesting you pay for it, just close the box & it's fully functional forever.