Loft beds are a smart solution in small homes because they free up so much floor space for play, study or storage. But young kids may not be ready for a high loft so a compromise is a low or junior loft bed. You won't have the same amount of head clearance below, but it still adds quite a bit of usable space to a small room.
Some of the factors you'll want to consider: just how high is it? do you prefer an angled or straight ladder? how tall/long of a guard rail do you want? how much do you want to pay?
I can't answer those questions for you, but above are five low loft beds to get you started. If you're doing an internet search, try the search terms "low loft bed" or "junior loft bed". Do you own a low loft bed? Do you recommend it?
2. Twin Wood Loft Bed with Desk and Shelving in white or espresso. 46" high. $299. (Walmart)
3. KURA Reversible Bed. (bed can be lofted or not) 45.5/8" high. $199. (IKEA)
4. Canwood Whistler Junior Loft Bed in hite, natural, cherry or espresso. 45.67" high. $199 (Walmart)
5. Windsor Low Loft Bed with Bottom Curtain. 43" high. $599. (Target)
(Images as linked)