Red or yellow ackies. They are real easy kinda pricey but stay small and very pretty. Most monitora are going to get good size. Blue tongue skinks are awesome and you dont have to feed protein. Have you thought of those at all?
How much do you know about monitors? Have you kept them before? Are you wanting a lizard you can handle or just a display? If it's to handle i'd suggest a blue tongue or bearder dragon. If you want a big lizard to handle get a tegu, not a monitor. Just my 02
As has been pointed out by both Kelly and jtrux monitors are a reptile that requires some special care. Even a small monitor such as an ackie or timor (which I have) require a sizeable enclosure (my 2' timor is housed in a 4' x 4' x 6' aboreal enclosure), require appripriate diet (ground turkey or dogfood don't do it), and lastly they are a display animal like tropical fish (they don't enjoy handling and can have sme unpleasent, smelly reactions to this). I would suggest for a handleable lizard a beardie or bluetongue. If you are still interested in monitors research, research, research. www.mampam.com is a good site.
Even the smallest of monitors require fairly spacious housing, bigger than the "average" glass tank. Ackies are fairly more resilient and hardy, but their price and lack of ready availability is what keeps most beginners away. Don't let that stop you if you really want one. Save up, and shop around online for a reputable breeder or dealer. Pet stores are not the only place to get reptiles, you know.
PLEASE do NOT get a savannah monitor! While small and cheap, these lizards do get large (3-4 ft) and require a custom cage at least 8x4x4 ft. They are not for beginners.