I am building a 7070 and have three spots left to fill - the Draped Bust and Classic Head large cents and the 20 cent piece. I have tried to set my minimum grade at VF and try to get most coins at XF or better. Newer coins tend to be proofs or uncirculated. Some like to have their set in all one grade but I think the progression from older VF to AU/MS also makes for a nice presentation.
It's all going to come down to grade. I can't realistically afford to build an AU or MS set at this point; but I don't like coins much less than VF because a lot of the detail is just not visible anymore.
Some general comments on what some of these coins have cost in my experience at this level. Note I spend a lot of time looking before I buy, so I try to get good prices rather than fill a hole quickly:
johnny54321 is right about the older large cents - I am probably going to have to shoot for lower-end VF and those two are probably going to run me $1000+ in VF and it's going to be a hard search
The remaining 1/2 cents and large cents can probably be had for $50-100 each.
The small cents and 2/3 cent pieces - there shouldn't be anything here over $100 probably and many can be had for under $50. Of course the newer ones less. The two and
Three Cent pieces vary. It's tough to find a nice
Two Cent Piece - the In God We Trust wears easily; the silver 3 cent is so small I can barely see it anyway so I went lesser grade; the
Three Cent Nickel wears well and so they are not that difficult to find.
I think I got all my half-dimes for under $50 each and the nickels aren't too bad either - the Shield with Rays was the toughest for me. The same is mostly true of the dimes as well. I think there is no coin that went for over $75 in this group for me.
The 20 cent piece is probably going to run me close to $200. The bust, seated and
Barber quarters all cost me between $50-100 each. The Standing Liberty Type I is a tough coin to find in a nice grade. I think that one went for north of $100 for me.
Half dollars. These can start to get pricey. I think $100-200 each for the bust and seated; the newer ones are less - I think all under $50 each for me. The toughest I think is the Capped Bust Reeded Edge. I wanted classic commemoratives and I wanted specific ones - the Columbian half is pretty inexpensive (less than $20) but I also wanted a Lexington, a Pilgrim and an Oregon Trail and these ended up around the $100 each range.
Silver Dollars. Besides the early cents, these are the other budget busters. The
Seated dollars are just plain expensive. Plus they are often counterfeited, so certified/slabbed or a trusted source is important. It's easy to spend $300-500 on each of these. Same for the
Trade dollar except maybe a little less - $200 perhaps. The remaining dollars are all pretty easily available for under $50 each as is the last page containing bicentennial and modern coinage.
So if I add this all up on what I think it would cost to build this today, I am thinking I have about $4000-5000 in my VF or better, mostly XF or better 7070.
It's a great set to build and worth every penny in my opinion! Good luck if you decide to go for it!