I started off my imaging using an alt azi mount and 80mm scope.
The scope was too small image the planets, but, once leveled and well aligned, I could get 20 second long exposures through the scope.
20 seconds may not sound like much, but it's enough to capture the brighter nebula and galaxies.
You just need to take heaps of shots. I'm talking at least 100 photos, more if you're up for it.
You can also buy a dovetail bar so you can attach your camera with lens to the mount. You'll be able to take exposures as long as a couple of minutes, depending on your lens.
It's not ideal for astro imaging, but it will get you started. You'll learn about setting up your rig, how to align, how to frame your shots, how to achieve fine focus and how to stack and process your images.
It should keep you busy for a year or two. Enough time to save up for the next step up in gear which will cost at least $2000, if you buy second hand.