It depends what the starting bid is. Your sellers fee of the sales price will be 0 dollars if it sells for 1k or higher. They have a small listing fee they do charge based off of where you set the minimum bid. 1-99 dollars costs you $3 100-999 costs you $5 dollars and 1000+ costs you $10 So if you sold any coin for 1k or more it could be as cheap as $3 but the most it could cost you would be $10.
I would guess including the BP, since that's a cost of business which the state has nothing to do with. It is always part of the selling price, just not a part you, the buyer or seller, chose.
I believe @SuperDave is correct. Although I've only had 1 time I needed to add a purchase when.my invoice of 2 items was around $1120 so to avoid needlessly throwing away $100 I bought a 2011 ase anniversary set pcgs 69 for $450. Meaning that all 3 items passed $1500 before the bp so I'm uncertain. I do like the silver lining feeling that the extra purchase net cost was less the tax, meaning I technically only paid $350 for the ase set, but if I didn't live in California the tax would be a moot point. Same goes with Heritage as they have a satellite office in Cali
I remember one dealer saying to me many years ago - Buying is easy - selling is the Difficult part. Another factor is where is the coin going into or coins you have to sell. In their PRIME TIME Signature sale or mail bid/Internet only (i.e., non-floor)??? Also - will my coins go into a bulk lot. Although with Stacks/Bowers some coin are hidden all together but with Heritage each coin in the bulk lot gets a photo from my experience. (Huge). Unfortunately with myself I am LOCKED into Stacks/Bowers as a good part of my collection is contemporary circulating counterfeits. However, I may consider selling some of these through secondary auction houses if they become bulk lot'd or not pictured. Normally to get a picture a coin usually needs to be valued more than $200 although with Heritage everything seems to get a photo. Its difficult or should I say using multiple auction houses today may be in order. One thing I noticed is the old Stack's lot descriptions in the 70's-90's are gone on bottom end stuff ... a lot of it today is one liner's ... but Heritage does get a wider audience even though the lot descriptions may be one liner's and cryptic - just reciting what's on the slab. John Lorenzo Numismatist United States
Back when an auction involved mailing out hundreds [or even thousands] of expensive to produce and expensive to mail catalogs, I could see the 15 - 18 % buyers fee. With online catalogs the norm now, I don't see the justification. But as the psychological studies have shown, one you have a benefit, it's hard to give it up, even if no longer justified.
Pictures still need to be taken. Print/copy still needs to be written. Now you have an electronic platform that needs to be maintained, protected and continually update/upgraded to stay ahead of the competition. BTW, HA still sends out catalogs. IMO, the costs are necessarily going down.
Ask yourself this question, if the 17.5% BP is so daunting, then why is HA the largest coin auction site in the world? I myself buy many coins from their auctions. I factor in the BP when bidding. I buy from them because week in and week out, they have some awesome coins up for auction. Their website is light years ahead of anyone else in the industry and I've always had good experiences with their customer service.
I mentioned previously about Stacks/Bowers and group lots and not all coins being pictured - HOWEVER - their new website - Internet only seems to have resolved this issue and the problem of paper cataloging $50 items or so ... much improved ... but as you say ... keeping up with BIG DADDY (Heritage) or at least trying to ... MY COLLECTION. Some nice bell and whistles ... Heritage. JPL