It all depends on location and demand / supply. You can get modules relatively cheap from Japan (Yahoo!), even with handling / shipping service (I typically use From Japan).

SC-55MKII: $50 (not boxed)
MU80: $50 (not boxed)

Both can go up to $200 when you buy them on eBay (complete, boxed, with shipping) for convenience. Like anything it is a matter of hard work (e.g. searching / waiting / negotiating / assuming risk) versus convenience (click, pay, wait for the mail). I bought a SC-55 for $45 shipped and a SC-MKII for $65 shipped recently. And I can usually source MT-32s for $55 shipped average through Craigslist usually.

I can not buy from ebay, and i have never done any buying via yahoo, so that is a bit of a problem 😀
I have found an MU80 and SC55MK II both for 50 euro here in Serbia, thats why i wonder.

EUR 50 = $80. That is a fair price. It is all about effort. When you put time into something you can get it a lot cheaper most of the time. When you want something right away you usually pay more. 😀

Modules are very common and cheaper usually than the cards. Musicians use modules and consequently many more were produced and many more survived. Fewer cards were sold (expensive already in the day) and many did not survive (computers were recycled: including cards). Some modules are more valuable: CM-32L, CM-64, CM-500 and MT-32 generation 2 especially. CM-32P, CM-300 and MT-32 are relatively cheap. Especially the MT-32 is very common (in the USA) and thus the cheapest but also the most popular (for obvious reasons). 😀

NIB MU80, $150 + $40-50 worldwide shipping from South Korea. That man also sold NIB SC-55 for about $150 too (or was it SC-88? I forgot and it is already gone from sold items).

Thus, higher than that, it's probably a greedy seller. There is one in Moscow that wants $300 for a bare used MU80, and $200 for a FB-01. I tried to negotiate but he won't budge. He tries to sell that for more than year already 😉

I see. Ok. 50 euro sounds OK for SC55 than. Thanks for all the replies 😀
Ive seen an FB-01 for 50* euro, used.

FB-01s should be EUR 30. It is a pretty basic / useless synthesizer. For PC gaming it is only supported by very few games. Basically an IBM PC Music Feature in a box. Very much like the MT-32 compared to the LAPC-I. 😀

Right, FB-01s are very frequent. They have built-in PSU, thus one should consider FB-01U for 110V and FB-01G for 220-240V. They usually sell about €30 at ebay.de; however, mint condition ones could go up to €70.