The College Level Examination Program offers a college mathematics test, so any practice exams related to this test are useful. Accuplacer college math practice exams and colleges' own sample tests are other likely resources.
The CLEP exam for college math assesses a test taker's knowledge of material covered in a freshman-level math course. Passing the test involves passing routine problems as well as those that require an understanding of math concepts and applied mathematics. College Board puts out official practice tests for this exam, though sites such as 4Tests.com put out free practice questions.
Accuplacer is a placement exam for different subjects, including college level math. The topics include algebra, math equations, geometry and trigonometry. CollegeBoard.com offers free sample questions as well as official practice tests for this exam.
Sometimes universities utilize their own placement exams for college mathematics. For example, the math department at the University of Maryland uses a multiple choice placement exam covering concepts ranging from routine problems to applied math. The math department features a sample placement exam that includes several grading options.
Wisconsin State University utilizes a similar system. The university features a practice test with 36 problems. The practice test lists the problems according to math concept. Links within the exam also take test takers to explanations of the math concept. WSU advertises that getting 33 out of 36 problems correct signifies readiness for college math.