We're planning to EFF our next LO right from the start and I'm wondering what everyone's favorite formula is. We used Enfamil Gentlease with DD#1 because she had some issues with gas but we're sort of hoping our next LO will take to a less expensive formula

I've heard good things about the Walmart brand and also the Costco brand, I think? Also, if we do end up wanting to try a "gentle" or other special type formula, does anyone have any experience with the store brand specials? I know that we'll need to try them out and see if our LO likes them but I'm wondering about everyone else's experiences. Thanks in advance!
Re: What's your favorite formula?
As a side note, we also just started our LO on a new probiotic we got from Whole Foods called Nature's Way Primadophilus Children. Our LO was always pretty gassy (no matter which formula we used) and only pooped every other day. Since starting on the probiotic she is pooping usually every day and seems to pass her gas easier. We had 1/2 teaspoon of the powder to her last bottle. Just figured I'd mention it since you brought up the gas issues.
BFP #1 12/29/10 EDD 08/29/11 Blighted Ovum 02/09/11 D&C 02/11/11
Clomid 50mg BFP #2 09/21/11 EDD 05/29/11 Chemical Pregnancy 10/4/11
BFP #3 4/19/13 Beta1- 106 Beta2- 524 Beta3- 3500 EDD 12/22/13 LO born 12/31/13
We originally started LO on the Gerber Gentle formula, since that's what they supplemented her with in the hospital. Around 6-8 weeks she started to get really bad reflux (or maybe colic?), so at pedi's recommendation we switched to Enfamil AR, which helped. Her reflux got a lot better around 12 weeks so we've since phased her onto regular Enfamil and now Target brand.
We did try her on the Gentle again at one point since we still had some left, and it actually made her a bit refluxy again. I think since it's broken down more, it might be a little thinner and, at least in her case, easier to come back up. She seemed to do best on the regular stuff, but I like that with the probiotic she is getting some of the good bacteria she would get from BM, and the fact it helped her gas and pooping was even better