As both products are good,order the

_______ one from the_______ competent of the two clerks.

cheaper, more
cheapest, most
cheaper, most
cheapest more

When comparing two things or two people, use -er or more.

Both of your comparisons in this sentence require the comparative form of the adjectives since the words "both" and "two" indicate comparison of two (not three or four or ... ) things or people.

=)