Does informing someone of the costs of Hajj out of fear of lying make the informer one of the hypocrites (al-mura'in)?

There is no harm in disclosing what was spent on Hajj, especially if asked about it. Whether this falls under showing off (riya') and seeking reputation (sum'ah) depends on the intention. Riya' is performing an action for people to see, and sum'ah is performing an action for people to hear about it, in order to gain a benefit, glorification, or praise. If you have no such intention, then this is not considered riya'.