A lot of the $8-15 bottles could be likened to the big "internet brand" cigars. Nothing wrong with them. Some gems in the bunch. But a lot more searching to find something that really wows you once you've had amazing wine to compare it against. More often than not the wife usually comes home with something more in the range of $20-30 bottles. But, I'm always seeking deals, too. One of my favorite "mainstream" cheapies is Gnarly Head Old Vine Zin. (and you can usually add a good rebate to the mix multiple times a year) It's my old reliable "cheap" wine, coming in well under $8/bottle after box discount and rebates are figured in. Note, a true Zinfandel is not the "White Zin" your mother drinks. Not as fruity as the Cab your looking for, but a flavor BOMB and screams for a nice steak. More in the Malbec or Shiraz spectrum. You can't lump all reds or all whites together, either. Like saying all cigars taste the same since they're all just tobacco. Port is AMAZING with cigars, and can be like a 5 star restaurant gourmet dessert in a glass. Don't write off whites, either, and don't limit yourself to specific varietals or regions.
Oh, and don't get too caught up in all the gimmicks. Don't think that you NEED to decant. There are definitely wines that benefit from it, and most of the time they will not be the cheaper mass produced wines you're going to start your journey with. Spend money on good glassware before you do on a decanter. Hell, we've done strictly wine-based travel if that gives you an idea of importance in our lives, and I'm yet to buy a decanter. Try every wine when you open it, pour a glass, swirl it around, let it sit a bit, and try it again. You'll start to get a feel for what you like and what a wine needs just like you experiment with RH and temp in your humi. There are no right answers, just answers that work for you. Most importantly, enjoy it!
RAMBLERAMBLERAMBLE... I'll stop.