Husband loves Killians Irish Red. . .
It won't be less expensive but Total Wine & Spirits carrys several beers by Ayinger out of Germany. Many of their beers are darker and low hopped like Killians. I'd suggest you check out Ayinger's Dunkel, Brau Weiss, Doppelbock and Ur Weiss. Ayinger is one of the few widely available yet outstanding foreign breweries around IMHO.
Take him to a local brewpub and get a sampler. Microbrew beerfests and in-store tastings are a good way to figure out what you like too. Or seek out a decent beer store in your area, and ask if there is someone knowledgeable about beer to give you some recommendations for singles to buy and try.
Probably not going to find much that is cheaper though given that Killians is made by Coors and can be found in supermarkets, Walmart, Costco, etc.
That's a tough one...Killian's is pretty darned cheap AND _very_ widely available.
I've certainly had better beers, and many worse ones...for the price, Killian's is not too bad (though it was more flavorful when it was first introduced 23-24 years ago and marketed as an 'ale').
Most alternates I could name would probably be more expensive (and less widely available). Actually, Budweiser American Ale is fairly similar and may be cheaper...if he really likes Killian's he'd probably like Bud American Ale. (I'll duck now, because my fellow "good beer" beer geeks will be coming after me)