I’m a BIG fan of bodyweight workouts these days. I am not currently working out at a gym, so my workouts include things like spin bike workouts, walks, body weight circuits, yoga, stroller strides, etc. and with bodyweight workouts you get a lot of bang for your buck. Strength + cardio in 30 minutes or less. Boom. These are also a great option if you are on vacation, you just can't make it to the gym, etc.
There are a ton of body weight workouts online. If you plan on going this route (which again, I highly suggest), be aware of any injuries you may have. Bodyweight workouts tend to include lots of squats and jumping, so be careful if your knees are bad! In addition to injuries, be aware of how your body has healed after child birth. It's normal to feel like your abs are weak or you hips are out of whack, etc. Make sure you have the okay from a doctor before starting to workout again!
Also- If you can only do a couple per week, then it’s no big deal if they are full body workouts (like the one below). However, if you plan on doing a bodyweight workout 3+ times per week, then split up upper and lower body workouts so your muscles have time to rest and repair before working it again.
Here’s one of my favorite full body workouts.
1 minute Plank
35 Jumping jacks
10 Lunges -each leg (to take it to the next level do jumping junges)
10 Tricep dips (do this on a stable chair with your feet on the floor- video example here)
35 Mountain climbers
Repeat 3-5 times and cool down!