For Prime members only, Amazon offers the Mongoose Men's 26" Dolomite 7-Speed Fat Tire Mountain Bike
in Blue, model no. R4144, for $173.62
with free shipping
. That's $5 under last week's mention and lowest total price we've seen. (It's the best deal now by $20, outside of the mention below.) It features an aluminum/steel frame, 7-speed rear derailleur, 4" alloy rims, and 4" x 26" tires.
A close price: Walmart
has it for $179 with free shipping.