I have been looking to get back into lizards. When I was a teenager I had two lizards (false chameleon and a baskalisk) till I joined the Army and gave them to my friends.
Now talking enclosures, reptiles can definitely be done cheaper than a fish.
If going small then its about the same really. Where reps pull ahead is large enclosures. Like mentioned can use non water tight fish tanks or even build your own for way cheaper than getting big tanks for big fish. I priced out all the materials to build one myself (4x4x8ft) and it was way under two bennies. You can't even but a new 75gal for under two hundred.
Looking at food I am guessing about even maybe. The one I wants brumates so will only have to feed it for half the year. Also some of the food can cross over for both (crickets, worms, roaches,tilapia,shrimp)