Help with posting to online classifieds sites

We need to have around 60 ads posted online each day for 1 week, on various sites (mainly classifieds e.g. gumtree, kijiji, craigslist) to generate leads for our business. Ads will be 5-7 lines and no selling is required.
We will provide a list of sites to post on. If have the ability to write small text ads yourself or adapt the standard ones that we give, depending on where you are posting, it would be preferable.
You need to be able to post at least 1 ad every 3 minutes, so that is around 20 ads per hour. So we estimate it will take around 3 hours each day max.
Possibility of repeat work if results are good.