Most monitors will readily accept rodents. Insects only (unless supplemented with vitamines, which I recommend) does not provide enough nutrition for your monitors. Rodents have bones, meat, organs...etc to provide appropriate levels of all nutrients.
You might want to choose an appropriate sized rodent, I prefer F/T and hold your breath...cut up! The reason I choose to do this is because when the monitors are small, I don't like messing with pinkies all the time. I feel like I get more for my money with larger feeder rodents and cut them down to pinky sized parts if that's what the monitor needs. I'm not saying go and buy a jumbo rat for your 7 mo. old ackie, but a med - large sized mouse would be the same volume as dozens of large crickets. Rule of thumb, if the monitor can't swallow the head whole, it's too big. Cutting it up also makes digestion easier, it's kinda like chewing the food for your monitor...mechanical digestion.
Pinkies, or fuzzies are fine though if you have a problem with cutting up larger ones. They may be easier to digest as well, but for a larger monitor, why not feed it 1 $2 rat cut up then 6 $1 mice? I just find it to be more cost effective.
Other possibilities could be small chicks (when monitor is larger), roaches,...etc.
Any warm blooded feeder, like mammals, avies...ect could be used. There are a number of distributers out there, I would suggest rodentpro.com as worthy of having a look.
Hope this helps,
Tim