@antidroid and @dobey It seems some providers will support these phones if you've already had them on their plan for a number of years. They won't boot you off, but they won't let you bring any of these phones into a new plan.

@dobey and @Keneda and @TotalRando Went to T Mobile. They had adapters and set me up with a prepaid month on 2G for $15. Works fine, but like @Lt-Dillinger said... no data. That's fine with me too, but I'm also setting up a couple other Nexus 5's for my friends. They'd like to have a data plan, so I'll look into the Walmart situation for them. Thanks guys. That was all very helpful! Oh. What's a BYOD kit?

@totalrando Gotcha. Thanks.

@dobey Okay. So I had my phone set to "2G only." After switching to "2G/3G/4G," I'm all over the internet smokin' fast. This works as well as my iPhone. I am stoked! Thanks again to everyone here. I never would have figured this out without your help because all the service providers (including T Mobile) claim they don't support these phones.