All Stellar accounts must maintain a minimum balance of Stellar Lumens (XLM). 


The current base is 0.5 XLM and min 1.0


Each asset that you trust requires additional lumens plus sending requires some minimum balance.


So to trust Trust/Accept 3 tokens such as  EURT and TEMPO and MOBI you would need


(2+3) * 0.5 = 2.5 Lumens
 


plus a bit extra for sending and receiving.


If you just want to use the EURT you would need to have 1.5 Lumens (plus some extra for sending).


https://www.stellar.org/developers/guides/concepts/fees.html