The present invention is a new and non-obvious method for the improved and simplified purification of nucleic acids. A network connection is established between a server computer and a client computer over a network. All the foregoing processes are automatically completed by the computer system, which avoids human participation. Consumers can search and purchase one-time use coupons based on the coupon offerings. In some embodiments, hydraulic pressure within a cam phaser is varied in a manner that maintains the phase of the camshaft substantially more stable through transitory variations in torque applied to the camshaft by the actuation of the valves than would occur without the variations in hydraulic pressure. Three exemplary types of bid composition restrictions, which may be applied either singly or in combination, are disclosed: non-additive activity restrictions, subset restrictions, and superset restrictions.