You get what you pay for.
There are exceptions but unless you have been dealing with hand tools for a long time the chance of getting the exception is very low.
At that, the new lithium battery powered one last longer, not run longer but last longer before you need a new battery pack.
They DO run longer but lithium does not give you the -- I am running out of juice-- warning you get with Ni-Cads. They will just suddenly stop.
The money, for longevity, you pay for a gas powered one is a far, far, far better expense.
I just replaced the Ni-Cad batteries, the individual little AAs, for my two drills, five packs.
Total cost was $340.
They are both over ten years old but the battery packs were from useless to very short life for several years already.
I also put new rechargeable AAs in my 3 Leica battery packs for 25 dollars each.
The reason I took my drill packs to Batteries Plus without first asking price.
Replacement battery packs, on line, are 100 dollars, from Canada and not much more from Germany, with shipping, for some reason that just does not make sense.