Just know that enclosure will only last till the bearded dragon is 12 months, once they reach a year old they need a 75 gallon at minimum (basically 48x18x21). A 4x2x2 would be preferred but 75 is close enough if you can't find or build your own tank that is that size.
You may even save money going for the adult enclosure rather than slowly upgrading, as when petco has their dollar per gallon sales its generally only about 97 or so for the 75 gallon tank. Of course you'd have to either buy or build your own screen lid however.
For a 36x18x12 (Or a 30 or so gallon tank) probably a Reptisun T5 10.0 22" with a reflective fixture at the very minimum.
If you go with 75 gallon right away then personally I'd go for a Reptisun T5 10.0 36" with a reflective fixture. (You can also go for a 46" but if you want to save a bit of money the 36" will do)
And of course theres also good brands like Arcadia with their Arcadia T5 HO 12% and 14% bulbs.
These bulbs usually need to be replaced every 6-12 months on average.