I've had pretty good luck getting lots of dateless and partial date
Buffalo nickels off of
ebay. They're "grab bags" in that they could have anything in them. A lot of them will probably be junk, or just common dates, but there will be some good coins in there too. Check out my
rag-picking Buffalo nickel project to get an idea.
The key is to hold out for a promising lot you can get cheaply once you factor in shipping. For example, if it's a lot of 5 rolls (200 coins), and the shipping is $5.95, I won't bid more than $24.05 to be sure I'm paying 15 cents or less per coin. Or if I think the coins are particularly cruddy, I'll set a lower per-coin limit. There are auctions finishing every day, so be patient and get one at a good price. If the lot you want starts to even get a little bit high, just let it go and move on to the next one. There are lots of fish in the sea, and these fish are particularly fungible. I got one lot of 500 at 11.7 cents per coin because there were quite a few ugly ones and acid dates, but there were some really good coins in there too!
You also don't want to get lots where all the mintmark coins have been picked out, because those are usually the valuable dates, so be sure to ask the seller if there are any mintmarked coins in the lot.
In just a couple lots of "junk" nickels, I've found a 1913-D Type 2 and 1921-S, which are both key dates and valuable coins, and I still have hundreds to search through.
Another way to get a "grab bag" and collect coins cheaply is coin roll hunting. Buy rolls of coins from the bank (lots of rolls), search through and pull out the good stuff, and then take the coins you don't keep back to a different bank. That way you can build a collection buying coins basically at face value. I find an average of 1-2 silver
War Nickels and 1
Buffalo nickel in a box of nickels ($100 worth). A box of dimes ($250 worth) usually gets me 1-2 silver dimes, and occasionally a
Mercury dime. I find about 17 wheat cents in a box of pennies ($25), and I even found a 1903
Indian Head penny. Plus you'll find all sorts of weird foreign coins and error and variety coins. Some lucky people even find old
Walking Liberty half dollars, Peace and
Morgan dollars,
Barber coinage and all kinds of amazing things.
You do need a few hundred bucks in cash to get started with coin roll hunting, but since you're turning 99+% of the coins over every time, the net cost is extremely low.