Srixon Soft Feels (19.99 a dozen). Usually get them at either Edwin Watts, Golfsmith (now Golf Galaxy) or Dicks. Sometimes they offer a 15 pack for the same price or 2 dozen for $35.00.
The new version is a 60 compression rather than a 73 compression. Haven't played the newer version yet as I still have some of the 73 compression balls.
Z Star, Q Star, Soft feel and sometimes Cally tour and chrome soft.
Buy new
Bridgestone Treo Soft right now. Love the feel and distance. Rockbottom Golf.
I use Callaway Super Soft in the winter and a mid grade ball in the summer. I usually buy from a used golf ball retailer on line. I usually only buy new when I new ball for the year comes out and I want to see how it performs for me. I have a couple dozen Srixon Zstar sl yellow that I will start using when the weather gets warmer. After that I am not really sure yet.
I like the K-Sigs, got then from Costco and have about a 5 year stash! 
I use the TM Project (a). I have purchased the last several doz from TM's website cause I like have the #24 as the ball number and also a shamrock emblem.
Mix of-
Top Flite d2+ feel/distance, Maxfli Revolution Control/distance, and Bridgestone B330 RXS during spring/fall
Z Star xv, TM tpx, Snell MTB, and B330 when it warms up to 50+ consistently
The tpx's are the bees knees IMO.
I too am a Project (a) player. I bought some new ones from someone on the old FGI site. I've also purchased quantities off of ebay or lostgolfballs.
My backup balls off the bench were Titleist NXT and NXT Tours but they have been dismissed from the team due to off the course issues. One of the articles about the KSIG/Costco pissing match also highlighted several other suits/litigation Titleist has initiated against upstarts. I don't like their bullying tactics.
I have a sleeve of each of the Bridgestone e-series balls and I'll get them out to test this spring.
Callaway Super soft yellow ball. I am going to try out some Kirkland balls this year too. I get the Callaway balls from golf galaxy or dicks, local Walmart sometimes. Kirkland, the one box I have were gotten at a Costco store. Not easy to find
In general, I go with what I find, where there's probably a ten year stash in the garage. I play the cheapies, too. I've gotten the buckets of yellow Q-Stars from LGB, I guess I'm a bit partial to them. At the end of the season, I'll sell the decent condition Pro V-1s I've found in one lot. The hard balls are fine except when I short side myself. The ones I find I don't want get hit on the range at the course, where more than half the balls aren't range balls anyway.
Srixon Trispeed Tours, I got 2 dozen @ Dicks when they were buy 2 for $30, and then received another 6 dozen as gifts. So I've been set for a while.
I also like the Project (a) ball, and have 2 sleeves from Taylor made when they ran their promotion last year.
Preference goes to Z Star XV, Provx, NXT etc, but to be honest, I buy about 2 dozen a year and the rest I pick up as I play and put them on a relocation plan, which usually ends with them in the woods or fescue on the left hand side of another hole haha.
Usually I buy last years model, but don't play enough to worry about saving a few $$$.
Between now and June I will be deciding between:
2017 Srixon Z Star
2017 Pro V1 X
New Callaway Chrome Soft X
Outside shot..........Srixon Q Star Tour
During the season I usually play either ProV1x's or Srixon Z-Star Tour Yellows.
I did try the TaylorMade (a) ball while down in Florida a few weeks ago and was surprised with both how well it held up and the overall performance. Definitely a decent ball.
During the late fall/winter months I'll play just about anything that hasn't been beaten to death already.
I generally buy my balls at my club's pro shop... primarily because I'm cashing in pro shop credit every few months and balls or gloves are always a good investment. And I like supporting my club, which helps keep my dues down in the long run.
Picked up 2 dozen TM Project (a) from Meijer on clearance last month. I played them at the beginning of last season and liked them a lot. Also like the NXT Tour and ProV1X. The later are on sale at my local GG for $39/doz. I tend to play a lot of what I find, also.
I have been using the Wilson Staff Duo since it came out. Using the yellow ones for the the last two years. I used to buy them when Golftown would put them on sale for 2 for 1and now have 11 dozen on hand. I ususally find more balls than I lose. The Prov's and similar balls I give to a friend(who will buy me a dozen balls or something at the end) of the season and the rest I hit out onto out driving range.
Straight off the driver is my key criteria and I have found that most TM (esp the Burners) and Bridgestone E6+ are best. The Wilson DX and PX are good for this too, but lack feel off the putter.
I always try decent pick-up finds, but have yet to find a prime grade ball that holds consistent straight for me on drives. Good balls (e.g. Pro V1) I pass onto partners. Cheap 2-piece are range fodder.
Probably difficult to get the Burner and E6+ now, so need to find another go-to.
I've been on a kick with Wilson Staff balls lately. The Duo and 50. I like them and they're pretty cheap ($12-$20 a dozen).
I like the Wilson duo balls, too.
