Have you looked at purchasing it directly? Assuming the shipping isn't crazy, it should cost a lot less.
https://dmmcheckplus.com/shop/ols/products/dmmcheck-plus-without-enclosure
If you are on Europe, the full-blown version with LC, dual frequency, enclosure, etc, sets you back €239 on welectron, shipped, and you can have it ISO calibrated for €85 (plus shipping, I guess).
On the page you provided, a similarly equiped deviced would be $197.50 plus shipping. Shipping from the US to Europe is often ridiculously expensive so I bet it's cheaper to purchase it in Welectron. Not to mention that you would also have to pay VAT for item's price + shipping. Not to mention the piratic fees Western couriers charge for customs paperwork. Probably €50 more for an import in that price range. If you send it back to the US for calibration, you'll have to deal again with customs... probably twice. So, to purchase it in the US? Thanks but no, thanks.
Certainly it's not cheap, but since I didn't have any referencies, and those doesn't seem to be cheap either, it seemed a reasonable deal to me. So I got one to check all my multimeters. To me, main advantage is the availability of a calibration service in Europe. Should my multimeters disagree, I will not need to wonder which one(s) drifted, but I will know it for sure. Or so I hope.
However, I'm not planning to have it calibrated yearly. I'm planning to do it only if I'm seeing my meters disagree unreasonably. Now I have HP 3456A, Brymen 869s, DER DE-5000 (from Eleshop, not gray market -ouch!), UT61E and UT210E. While Uni-T meters are cheaper than DMMCheck calibration, I don't think replacing the better ones if they disagree is a very sensible option.
I think it would be also useful to get one of these multiple voltage references from some guy in the UK... but then we are again dealing with customs and Western courier/pirates, so... no. I would need to be able to have it purchased and calibrated within European Union before pulling that trigger
I wonder how I could get those referencies and get them calibrated without becoming a volts-nut and expending even more money in the long run. After having some looks at the Metrology section, I really got scared. So, to me, it's purchasing DMMCheck and perhaps some similar, voltage-related COTS product and to have it calibrated if and when deemed strictly necessary. For my needs and skills, that's probably already overkill.