The location of this retreat takes place in south Serbia, in Sesalac at the Voice of Nature Eco Center.
If you are arriving to Belgrade Nikola Tesla Airport you can get a taxi or a shuttle bus (much cheaper option, around 2-3€) to the city center.
From the main bus station there are buses to Sokobanja mostly in the morning. The schedule is: 7am, 8am, 8.45am, 10am and 1.45pm. The price is around 900 Serbian dinars (7.5€) and if you get a return ticket it’s cheaper (around 12€).
If you get to Belgrade late, you can take the bus to Aleksinac. Once there, the taxi straight to Sesalac can be bargained down to 20€. Else, there is the bus to Sokabanja and from there the taxi.
From Sokobanja there is a local taxi and here is their fb page with their phone number.
The taxi goes to Sesalacka Pecina (Sesalac cave) — remember “Sesalacka Pecina” as it may help the taxi driver who may be limited with English. The price for the whole car is 6-7€. Any other street taxi, you can bargain down to 10€.If you split it it’s not much. In Sesalac, the camp is all the way up for the most part. If you reach these unfinished triangle cottages, then you’ve gone slightly too far. Look for the Voice of Nature sign.
People are posting airport arrival times on the event Facebook group here: https://www.facebook.com/events/294430051442940/
Hitchhiking is another option but I am not sure how frequent the cars are, though bare in mind that Serbia is quite HH friendly so it could be doable.
If your flight is to Nis (it’s a small airport down south but some low cost airline companies operate there, such as Ryan air for example so this might be a cheaper option from your country) than it’s much easier and closer to Sokobanja from Nis bus station.
In case you cannot get ahold of Aleksander, Marjan Arsenov (the holder of the eco village) is available all the time on facebook messenger — Marjan Arsenov