leos are fairly low-maintenance, risk of salmonella is extremely low, im not even sure if leos carry it, but just dont stick the leo in your mouth and you will be fine lol, and no they arent poisonous, as long as you keep the cage clean they wont smell like a ferret does or anything like that. just need to spot clean its poo and stuff and every couple of months give the tank a good wipe down, and just make sure you keep their water bowl clean, can feed mealworms or crickets, insects will need to be gut loaded and dusted with vitamin supplements, wouldnt be very expensive at all, all you need is the heat lamp or even just a under tank heater, if you have a fish tank of any good size at all which you probably do if that is your pleco in the avatar then you can def handle a leo