The Moto G5 Plus is one of the best budget phones you can get, and it's available cheaper if you get the Prime Exclusive version from Amazon with ads. However, this already good deal is even better today. Both capacities are on sale for an additional $30-60 off.
The regular (non Prime) G5 costs $230 and $300 for the 32GB and 64GB versions, respectively. If you pick up the Prime versions, they're usually priced at $185 and $240. That's a good value, but now Amazon is knocking $30 off the cheaper version and a whopping $60 off the more expensive. So, the phone with 32GB of storage and 2GB of RAM is $154.99, and the one with 64GB/4GB is $179.99.
Considering how close in price they are, I'd go with the $180 phone. It has ads, yes, but they aren't terribly intrusive. You get a full-screen ad on the lock screen when there are no notifications and a single line when there are. There are also some pre-loaded Amazon apps. Still, this is a lot of phone for not a lot of money. I wouldn't wait too long on this deal. It could sell out.