I disagree with a convertible being a "waste of money."
The Evenflo seat that comes on sale this weekend for $109.99 is the Triumph 65. It has all sorts of features that might make it worth a little extra $$ especially as a Grandma seat. The no-rethread harness, for one. The harness height isn't quite as high as a Maestro, but it's high enough it will probably get him to booster age. It has a higher weight limit than a Maestro, so depending on his build it may even last him longer.
I always hear that it's a "waste" to buy a convertible for a FF kiddo, but is it a "waste" to buy a combo seat if you prefer a dedicated booster and won't use that function? What if there's another kid in the next couple of years? What if they have some kind of "wake up call" that convinces them to re-RF the kid, but then they're stuck because they can't use their seat that way?
I won't in good conscience recommend a FF-only seat for a child under the age of two even if I know the seat will only be used FF, unless there are no other good options available.