An inexpensive and robust optical trap system can be built from off-the-shelf optical and opto-mechanical components or acquired as a kit to be assembled in a laboratory. The primary advantages of such a trap, besides being significantly more affordable, are its flexibility, and ease of modification and upgrade. In this paper, we consider several important issues to be addressed during development and application of a kit system. We numerically examine the performance of trapping systems equipped with oil and water immersion focusing objectives. We also investigate the effect of trapping laser beam quality on optical tweezing. (Contains 7 figures.)