@Dca ****
Indeed the cost of a Laos visa at the border (Thai/Lao,Thai/Cam) has almost always been inflated in "other" currency. I've crossed at CK/HX many times over 25 years and the THB price was always based on some outdated/opportunistic exchange rate. On US passport, for example Lao VOA was $35 for many years, but they always charged 1500 THB (50 bucks). So now instead of $40 it's 2000b so it still pays to bring crisp USD and save around 600b.
Also funny/sad that the Laos gov't is demanding tourists use Lao Kip for their whole visit, not $ or ₿, but Lao border immigration won't even accept their own currency and local people will very happily take those other hard currencies. Also if you buy Kip on the way in it's a one-way trip cos they won't buy them back on the way out. LAK is soft and weak, especially now.
P.S. Yes this is the Thai Visa Advice group, but maybe just let this thread do it's relevant thing. Cheers.