The Red Rocks Sporting Goods in Miles City just got in a fresh shipment of maggots (or Spikes) and waxworms. They also have a limited supply of live minnows. These guys and gals have been very helpful to me, as I live a bit of a drive from Ft Peck Reservoir and am usually in dire need of timely info on current ice/fish/bait conditions up there. I intend to stop in on the way and give them some business. They are just South of the Walmart there off the second exit (coming from the West on I-94). Their number is (406) 232-2716.
Also, if you're heading to Ft. Peck, the Sinclair Station in Circle, Hell Creek Marina and the Lakeside Bait Shop at the North end of the dam, have live minnows and other bait/gear. Don't have numbers for them.
Also, in my earlier post, I mentioned Osprey Realty and the Minnow Bucket. There is contact info for them on the Walleyes Forever site (Billings Chapter). There is also contact info on that site for Hell Creek Marina (they also have their own web site, complete with current ice/fishing report).
Hopefully, this will help get you a close encounter with the fish of your dreams. LOL.
Tight Lines.