I have been using resistant stretch bands of increasing tolerance. I looked them up on amazon.ca and they vary in price starting at about $ 7.00 Canadian. Probably cheaper in the States. I do strength exercises with these three times a week. I started off with 12 reps x 3 circuits (that is about 5 exercises using the bands) and progressed to 15 reps x 4 circuits and I also started off with the lightest resistant band and now, after 8 weeks I'm on the second from the strongest. By the way, I'm 71 and was completely sedentary when I started this.
As for aerobics, get yourself some music - I adore ABBA - and dance to it non-stop for 10 or 15 mins. If your kids are around, they'll love it too - my grandchildren think it's a hoot. Good luck. But remember, just do what you feel you can without stressing yourself. Hugs to you, you've got a lot of people rooting for you.