What are you basing your prices on? If you're doing pulp (I'm assuming mostly first 3 decades of the 20th century, definitely before WWII) search for sears catalogs from the years you're looking at. Although there are pdf files out there, I think the easiest way is an image search. There's also a Canadian Eaton's catalog online at archive.org. I think it's Eaton's. A google search should give you both. I'm not sure what exactly you're looking for so I won't give a bunch of links.
I searched "gun price 1920" and came up with a bunch of stuff. Wikipedia says 200-450 for the price of a Tommy gun and the colt forum says 20-70 for a 1911. Wiki compares the gun to a Model A at 400 dollars. I think 100-200 is plenty for starting cash there. Remember every day expenses are low that you can live on a few dollars.
There's
this guide which links to the 1920's but lists 1800's and 2000's as well as the 20th century.
In a modern campaign I think it makes sense to treat houses and maybe cars as prizes. Cabs, trains, and such can be subsumed into Lifestyle, perhaps you do the spycraft 2.0 bit and assume everyone has some sort of car. Perhaps do a group van or something like that.
You can get pretty decently kitted up in most situations for a couple thousand dollars. Unless you're having your players buy every little thing (and I think that's where Lifestyle comes in) a thousand is probably enough. Low end guns, a fair amount of survival gear, even low end body armor can be bought on a budget of 1-2 thousand dollars.
I'd go with a budget of 1000-2000s/$ for modern games and assume they have a decent phone, access to transportation, and a place to live, all Lifestyle dependent. Unless you're having chases, the exact type of transport shouldn't really matter.
If you're ignoring booms and busts, 1870 to 1950 all bounced around 1/10-1/20 of today for prices. If your players aren't historical buffs, I'd go with 1/10 and 100 silver/dollars for the whole period.
Hope this helps.
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