This is what I do in my garage right now. If you're a beginner, front squats also force you to maintain better form than back squats.
Also try the hack squats (with a barbell as someone mentioned).
A third squat type to try is Zercher squats. You'll need something to set the weight on to start, maybe a couple benches. Try to find a picture somewhere (maybe Elite FTS, unless someone has one around here), but basically you cradle the weight inside your elbows and then squat.
For all of these start light and learn the technique, the weights will come. If you try to add weight first, good luck in trying to learn technique later. Try to find someone who knows what they are doing in your gym to watch your form.
Last comment. Keep working your deads, it's not a replacement for squats, but it is a great compound movement.