Hi Mamabear. I have the same bike, a little older, different name - Butte. Ugh. :-) But it's a fun bike to ride. Glad you got it for ... $40? Nice. You can find cleaner bars, tires if needed, can be had on CL for dirt cheap, stainless bolts at the hardware store, and other components from members here or at the co-op. It's a great project bike.

Go get some PB Blaster and lightly hit all the rusted or corroded bolts right away, a little down the seat tube where it might be stuck, and do it again the next day and even again after that, so they come loose easier. Spray some in the shifters too, might help. They will be gummed up and sticky at best. I think I have the same shifters. You can use that on the chain also to clean it - use lots of rags and keep wiping off the rust and gunk that will come out. Be sure to get oil on the chain before you ride. In your case, I wouldn't bother with expensive bike-shop chain lube. More important just to re-oil and wipe off the black gunk frequently.

Don't get any PB Blaster or oil on the bike rims or the brake pads. Keep a grease rag around and under the parts you spray to minimize getting it on the paint or your floor. Go easy.

The real winning deal is your willingness to work on it and learn. With 3 kids, they will also jump in and help and by the time they are in high-school you will have saved a ton on bikes, bike repairs, the kids will have something really positive to help keep them busy. Really a great start for the kids.