If you wanna buy any asset you can't directly tell owner, you need searching him in real life. I suggest develop bid system.
- you finding needed asset;
- if this asset selling on marketplace, you can buy it or send the bid, if not, you can only send bid.
- you send bid volume and life time.
- press "Create".
- your ENJ blocking.
This method have some minuses:
- enj bloked until bid expiration;
- on each bid you spend gas.
- you choose asset, push the button " I wanna it".
[- send the price.]
- each owner of this asset get notification on wallet.