I just stated promoted listings for the first time this month, will let you know the results as we get further with it... my $1./day budget has given me 8500+ impressions, 73 clicks and no orders yet.
Has been running for 9 days so far... what i know about impressions, clicks, orders/revenue ratios is this is I'm getting about an 8% click through rate. 9 days is nothing to judge this upon, but surprisingly, I'm seeing some valuable search term data that I didn't have before.
Standard industry online advertising that hits 2% or higher click through rate is considered successful, so I'm very happy actually with my numbers.
Bigger daily budget would have a bigger impact, I'm just not in that position yet to increase it.
You have to do what works for you and how you use the data can have a bigger impact on your sales...
Set a realistic goal and look at how much you can spend. Advertising is a long term commitment, just like selling or creating, you won't see anything happen overnight.
Basic formulas for you:
The formula for calculating CPM based on CTR and CPC is:
CPM = 1000 × CTR × CPC
The formula for calculating CPC based on CTR and CPM is:
CPC = CPM / (1000 × CTR)
The formula for calculating CTR based on CPM and CPC is:
CTR = CPM / (1000 × CPC)