For those who don't know what a proxy service is, this is a company that will bid on and buy stuff on Yahoo! Japan Auctions for you. Depending on the service, they may also allow you to bid on other auction sites or buy from on-line stores that do not ship to the United States. They handle receiving your items from the seller and shipping them to you. You'll pay a fee to them on top of the cost for the item, the domestic shipping (from the seller to them) and the international shipping (from them to you). There may also be a fee for packing your stuff up for international shipping that's typically included in their quote for it.
The upshot is that a proxy service makes a world of Japanese baseball card options available for a fee.
The proxy services that I have used the most - kuboTEN, JAUCE and Noppin - all charge fees that are based in part on the price of the item you're buying. For example, JAUCE will charge you 400 yen plus 8% of the price of the item. I got my 2021 BBM 1st Version set through them back in April. I paid 5000 yen for the set itself plus 800 yen (8% of 5000 yen is 400 yen plus the 400 yen flat fee) along with a 300 yen "bank fee". So my 5000 yen 1st Version set really ended up running me 6100 yen.
What's setting ZenMarket apart from the other proxy services is that they just charge a 300 yen flat fee for an auction. This means that the 2021 Epoch NPB set that I got through ZenMarket back in June only cost me 300 yen above the 2500 yen winning auction bid. ZenMarket's documentation says something about a 3.5% deposit fee for using a credit card or PayPal but I have never been charged this.
Had I used ZenMarket to buy the 1st Version set instead of JAUCE, I would have only paid 5300 yen for the set - the 5000 yen price plus ZenMarket's 300 yen fee. I would have saved myself 800 yen.
Their international shipping prices seem to be in line with everyone else. They will quote you a variety of shipping choices including SAL, EMS, Fedex, UPS and DHL - I'm not sure the other outfits have quite the range of options.
One other thing I like about them is they are pretty good about sending you emails to let you know when they've received your items and when they've shipped stuff out. One of my few frustrations with Noppin was that I had to constantly log in and check if they'd received the stuff I'd bought yet.
From what I've seen, ZenMarket's only downside is that they will only store your items for 45 days before they start charging you. Noppin and JAUCE will store your items for 60 days. This may not seem like much of a difference but it's going to make me have to ship the four sets I expect to buy in August and September of this year in two shipments instead of one.
I again want to thank Yeh for letting me know about ZenMarket.