Genealogy.com has an excellent (not all states) online index linked 1850 Census as part of their Genealogy Library subscription. Fortunately, Pennsylvania is one of the included states. The search feature is great. For instance, include keyword Philadelphia with name Charles Smith and the first file returned will include about 32 Charles Smiths from Philadelphia County. Click on the camera icon on any line and get the top half and the bottom half of the census page image as 2 pages.