I have a bearded dragon, and there are still some costs involved. I'd go by the higher figures, and consider yourself lucky if it costs less.
cost of owning a bearded dragon (please review several of these articles)
In the case(s) of these large(r) lizards, a lot of the costs are in housing, lighting (UVB) and feeding
(feeding my .5 kg. bearded dragon costs
several times what it costs to feed my 34 kg. service dog).
In your situation, there are some really nice (and gorgeous) reptiles you could keep for quite a bit less. Geckos make really nice pets, can be kept in much more economical enclosures, and those that are nocturnal may not require UVB lighting (check individual species). Being smaller, they're also quite a bit less expensive to feed, and many can thrive on prepared
gecko diets (even less expensive than live feeders).
There are many many other species of fascinating lizards of similar size & (less) expense.
Many are discussed on
Clint's Reptiles on YT. Reptiles Magazine is another source for interesting candidates.
best small lizards for pets (google search)
Just one interesting example that made my list—the
western fence lizard is a beautiful (IMO) creature, is available in the UK, and has a rare protein in its blood that kills the bacteria that causes Lyme Disease!