I just started a few months ago, was watching A4 Dominators on eBay for a while and picked one up at a good price. Did a lot of research and I actually picked up a Gridseed knowing it wouldn't make any real coin but I could at least experiment with running a mining rig without spending 4 figures. I've been running the A4 and I'm on track to get my investment back in the next few months.
I wouldn't try to speculate on the probability of making you're money back, just know that it's possible that the whole investment could go to zero. If you have any high interest debt, probably better to pay that down and avoid mining.
I saw mining as a more interesting way to invest in crypto than just buying coins. I'm really more into mining as a hobby than as a money making endeavor, I really like computers and networking so the whole thing just seemed fascinating.
Look into picking up a L3+ from Bitmain or look for a deal on a used script miner. I would say you're wasting your money unless you get a miner (or miners) that does at least 500mhs. If you have cheap electricity, you might be able to get a few older, less powerful miners and run them to get to 500mhs. I don't know for sure since I'm kind of just starting too but to me it seems like keeping up with the best mining tech is the best way to go, that's why I'd recommend looking into picking up an L3+.