Cost per mille (CPM) – the cost of gaining 1000 impressions for your Instagram ad – varies greatly from industry to industry, campaign to campaign. But according to WebFX, 46% of advertisers have a CPM of $4 or less on Instagram.
This means that the cost to reach 10,000 target buyers would be $40, and the cost to reach 100,000 target buyers would be $400 (though Instagram may decrease the CPM rate for larger campaigns as an incentive to spend more).