Not quite that straight forward if you're not located in the Netherlands 
Ranging from explicit warnings from the platforms to ship out of country (to avoid being scammed), the preferred secure payment methods of the platform, shipping cost calculations, etc. The seller would have to be quite forthcoming to accept an offer.
It sounds well, perhaps she seller could tell me the firmware installed.
They are not sold so cheap these days, they are at least 35+ but that would be OK.
The problem is I don't speak the language, and it is difficult to understand, perhaps with the help of an online translator.
Does people accept paypal usually?
Other problem might be sending it to spain...
thank you, I will have a close look.
I don't know the platform...
I have bought and sold a few things in ebay with no problem at all.
But the problem here might be the payment, if they accept paypal won't be so difficult.
Some will accept Paypal but not generally accepted. I never paid the asking price you can always bid.
I have asked a couple of vendors.
There are bids for 32€ that seems have not been accepted.
If they send it in correct condition and the firmware is OK, the price will be OK.
Has anyone gotten the buttons working? I have seen the WiFi button is defined as KEY_WLAN in the .dts file (here: https://github.com/openwrt/openwrt/blob/main/target/linux/mediatek/dts/mt7986a-zyxel-ex5601-t0-common.dtsi). In contrast, the WiFi button on my old router was defined as KEY_RFKILL, which used to work right out of the box to toggle WiFi.
//Edit: working now. I looked up /sys/firmware/devicetree/base/gpio-keys, WLAN button emits event wlan. But there is no handler for action wlan per default. cd /etc/rc.button then just copy the rfkill command cp -a rfkill wlan and voilá, WiFi button works as intended.
Maybe we should still change KEY_WLAN to KEY_RFKILL, so it works out of the box. Any downsides to this (can't think of any right now)?
Anyone know the correct method to enter OpenWRT uboot-mod recovery?
Does it have uboot web recovery?
Press reset button x seconds while plugging in power?
Also, what's the correct image to send over tftp? sysupgrade.itb?
Serial def works.
Depends on previous state, most likely the initramfs.
I used serial to flash the uboot-mod but for the uboot tftp recovery method, without the need for a serial connection, what do you need to press? reset while connecting power maybe?
I ask because my unit booted to the initramfs after a failed sysupgrade and wouldn't seem to flash the sysupgrade image.
If you're in initramfs already, you should be able to start from scratch, as if you had booted initramfs for the 1st time during initial install.
The method of OpenWrt installation without serial worked very well on firmeware version B4_0130
Thanks @thehybrid1337 for your work 