Is there any problem with receiving money in exchange for giving maaser or tzedeka to a particular person.
For example Reuvan has $1000 maaser and Shimon comes to him and says "give the money to levy and I'll give you a $100"
Or if levy himself comes and says "give me the $1000 and I'll give you $100".
Is it permitted to accept the money?
Even further may a person advertise himself that he has a $1000 of maaser to give away and he'll "sell it" to anyone for $100.