In this day and age, you can make a pretty reliable skimmer with an air pump, a woodstone, 2" pvc and some cut water bottles.
It helps to have the background of having watched a skimmer work quite a bit before doing a diy, and they are pretty ugly compared to the ones made with cast acrylic, but if budget is the mindset a home made one is fine.
A skimmer is just, generally, a very good thing to have, and a macro algae reactor should just be a supplement.