The internet is a useful tool...............
Use this chart to find the size needed for what you want to lift.
http://www.harringtonhoists.com/tech...67%20rev02.pdf
Then use this chart to tell you what the I beam size means.
http://www.advantagemetalservices.co...ons-chart.html
Then call your local steel shop and have a chair handy. You'll $**T at the cost of I beam. From what I see S8X18.4 is about $45.25/ft. So $725 for a hunk that would lift 1000#. If you want to be able to lift 1 ton, then about $951. That's the steel mill's price. I'm sure the local shop will need to make a little on those numbers.