Let's see. How long do you plan on keeping your Expedition? If you plan on keeping it for a long time, in my opinion, don't hold back. Spend the extra money and get a good set of shoes, cheap ones always fall apart. If you live in an area where you get a ton of snow, I'd go with the Nokian Vatiivas. I bought a set of these 8 years ago, put them on my explorer. Before I sold the explorer, I put them on my mom's Jimmy. She's still rockin them. Excellent on pavement, phenominal on snow. If you're looking for a good all-terrain that is pretty beefy and will last a while, The Bridgestone Duelers A/T are great too. The don'thandle quite as well in the snow as the Nokians do, but with a vehicle as heavy as the Expedition you'll be fine. Both tires will run 800-900 dollars all the way around, but they're both well worth the money. That price is also with the 15 dollar per tire warranty, which if you ever get a nail in one of them or one fails, you only pay the 15 bucks, rather than re-purchasing the tire for the full price. If you plan on sellin you're Expedition anytime soon, get some wal-marters.
Keepin mind, though, you get what you pay for. Hope I helped you out some.
Bridgestone Duelers A/T 265/70/17