It's possible, but i wouldn't recommand buying $5 from anywhere... There are a couple of reasons:
1) you'll pay a hefty premium
2) the seller will pay a hefty fee (and pass this price on to you)
3) you'll start gathering dust outputs, so you'll have to pay a big fee if you want to spend those again.


At this moment, https://bitcoinfees.21.co/ tells me that at current BTC price, you'll have to pay more than $1,5 fee for an average sized (226 byte) transaction if you want a decent chance of getting a confirmation in less than an hour...

It breaks my heart to say this, but if you're dealing in micro payments, it might be a better idear to switch to an altcoin instead...