You all are giving me much to think about. Lots of good information. Thank you!
I've been slowly trying to learn about DBI. It's a newer term, at least for me. I've always understood of DB of gain was compared to a dipole. But I guess DBI is a little different. Kinda sounds like antenna manufacturers are cooking the books to make their numbers look better.
The comet CA-712efc is the antenna I'm currently looking at. It seems to have the best performance within my budget.
I admit, the repeater is an inexpensive retevis. I was never impressed from day one, but come to find out the antenna that came with it was damaged from the factory. I've since repaired it and upgraded the coax. It's made a huge difference. I'm trying to squeeze as much performance out of it that I can. I'm upgrading here and there as the funds become available.
I'm also learning what I can about antenna gain. I've come to understand more about the higher gain antennas having a flatter radiation pattern as others have mentioned here. I don't think I have enough height for that to be a problem. I'm in flat, flat kansas. I only have trees to contend with.
I understand if it were a mountainous region, a lower gain antenna would help radiate upwards and downwards depending on the elevation of the antenna to the surrounding terrain.
These are all things I've been piecing together in what little time I have to devote to the hobby, I'm sure you parents will understand. Again, thanks for all your advise.