AT&T has just launched Samsung's LTE-based Galaxy Tab 3 7.0 tablet for $300 on contract, or $400 without. You can also get it for $20 per month ($480 in 2 years) with AT&T's Next program. The Wi-Fi only option is only $200, if you don't need LTE and want to get that instead.
I've never been a believer in LTE for tablets, especially 10" ones, which is what we've started seeing a while ago with the iPad with LTE and others. It makes more sense in a 7" tablet, because it's a lot more portable, so you might actually want LTE with you, so you always have Internet connection, no matter what.
This is why a tablet like the Galaxy Tab 3 7.0 might sound attractive. However, I'm not so sure it's this tablet with LTE that you should be getting for $300. The tablet's specs are not all that impressive for this price. What you get is less than even the old Nexus 7's specs: 1024x600 screen, 1GB of RAM, and a 1.2GHz dual-core ARM chip, with 16 GB of storage on board (with half of it most likely taken by Touchwiz).
For only $50 more, you could be getting a new Nexus 7 with LTE and 32 GB of storage, quad core S4 Pro processor (much faster), 2 GB of RAM, and a true "retina" resolution for this form factor, of 1920x1200. For only $50 more you get a tablet that is at least 2x better in every possible way from storage to processing power and memory.
I'm not sure what Samsung is trying to do with its tablets lately, but ever since the Galaxy Note 10.1 last year, their tablets have been very disappointing (with the exception of Nexus 10, but that project was mostly led by Google). The tablets they've released so far (up until the new Note 10.1, which actually doesn't seem too bad), have been very underwhelming in terms of both specs and price. Not only are they not competitive in specs with the latest tablets from competitors, but they are usually significantly more expensive, too.
Hopefully, next year they will pay a lot more attention to their tablets, but if they do not, we can always count on Google and its partners for the Nexus program (Asus, and presumably LG next year).