It is permissible to engage in business during the Hajj season and there is no sin on you if you buy and sell before and after Ihram.

Whoever is able to perform Hajj and delays it for no reason has committed a great evil and a major sin. He has to repent to Allah from that and hasten to do Hajj.

Hajj means travelling for the purpose of visiting the Ka`bah to perform the rites i.e., the actions and words reported in accounts of the Prophet’s (peace and blessings be upon him) Hajj.