It is possible to provide services in exchange for cryptocurrencies.
In a marketplace, there is always a scope of a scam. (Buyer underpaying or seller overcharging)
Some examples are
1. Orchid Protocol (decentralized selling of bandwidth) allows leechers to underpay, but mitigates the larger malice by requiring every user of the network to stake some coins before enabling any transaction. This reduces the number of people who will be able to perform leeching by means of a sybil attack.
https://medium.com/@gustav.simonsson/you-describe-a-viable-dos-leeching-attack-1cf01436974b2. OpenBazaar (decentralized Ebay) maintains a thread of scammers and a set of moderators who do some basic validation. This does allow a cheap adversary to make some quick money by "selling" something and never shipping it.
https://www.openbazaar.org/scam-prevention/What are some other examples of marketplace related dynamics to avoid buyer-seller scams from happening?
