There are lots of ways you can help kids get a little exercise in the winter without spending a lot of money.
If you’re looking for something your kids can do every day, clean out the garage. It’s completely enclosed so warmer than outside, but you have a barrier from the kids’ noise and there’s not much they can break in there. Put hazardous materials up high, sweep the floor, park the cars outside and you have a wide open space with the hard floor. Your kids may need to wear jackets, but don't use a gas heater to make things warmer. The fumes are dangerous.
Here’s a list of things our kids have done in the garage in the winter:
Play ball on a small basketball hoop
Hit a tennis ball against the wall
Slide on a small slide
Jump on a mini trampoline
I’m sure your kids will think of even more fun things to do.
If you want to get out, restaurant play places are totally free. If you don’t want to get lunch, just get some drinks. My kids don’t stay at the table long enough to eat anyway when there’s a play place around.
Go to a restaurant that is kept clean all around. If everything else is cleaned on a regular schedule it's likely the play place is too. Bring some hand sanitizer and sanitizing wipes if you want to do your own spot cleaning.
Bring a book and let your kids play until they seem tired. If you have a time limit, tell them beforehand. “We’ll stay for half an hour and then I don’t want any complaining when we leave.” After that, give them a five minute warning. This will help minimize whining when you leave.
Most malls also have an indoor play area. No purchase is required. Again, bring a book and plan on staying a while. Also bring snacks and a drink.