You cannot make money from any PR sites. however, if you are getting traffic and if you are ranking in google for some terms, you can make money by promoting affiliate products, adsense, or through cpa marketing.
make money I think careless to the page rank ,it depends on your conversion and traffic demographic.bounce rate and loyality,nothing more important that include Pagerank
I think you can sell link for your PR1 site but it will be very cheap. You can improve your PR to 2 and you will make more money
attract some traffic and become a member of some affiliate program or as adviced - adscense or sell text links
Make money online is totally depends on amount of traffic which is coming from Google so keyword should be in top ranking if you want make money online.
Many people are still confusing page rank and traffic. To make money online, you need traffic, not page rank! I have a page rank 0 site, but it has given me the highest number of subscribers!
PR1 site isn't really going to get much if you sell links. I'd suggest continuing to build backlinks to up your PR to 3 in the next update. Then sell some links. You could also make money just selling backlinks by blog commenting or forum posting for people.
I think traffic is very important than PR. Try to imagine, which one you will choose, a blog that have pr5 but just have not more than 10 visitors a day, with a pr1 blog that contain a very hot items and recive hundreds of traffic a day?