If you ever found one and they don't even ask for collateral, it is likely that they are a scam. In fact, most services are scams and their goal is just to collect your money. As mentioned above, a ton of legit businesses went bankrupt so it is unlikely that any legitimate service would risk themselves doing that. If anything, you'll probably find better luck to get a loan from your bank although the risk is so high it is not worth doing at all. Just do DCA and be patient, you'll eventually collect enough Bitcoin if long-term investment is your goal.