The Reciprocal Public License defines the notion of an "Extension":
"Extensions" means any Modifications, Derivative Works, or
Required Components as those terms are defined in this License.
and also specified what "Derivative Works" means:
"Derivative Works" as used in this License is defined under
U.S. copyright law.
The relevant section in the requirements of the RPL, section 6.1, states:
You must make available, under the terms of this License, the Source Code of any Extensions that You Deploy, via an Electronic Distribution Mechanism...
If, under U.S. copyright law, your larger work is indeed a derivative work of the code you're linking to, then your larger work is an Extension. Whenever you Deploy it (i.e., any distribution, and virtually any use within an organization, even privately), you must make your source code available (apparently to the public at large; I could not find clarification on who must be given access to the source).
The license forbids charging for distribution of the source code of Extensions beyond actual distribution costs:
You may not charge a fee for the Source Code distributed under this Section in excess of Your actual cost of duplication and distribution.
Presumably, you could charge for the binaries, but you'd also be required to publicize the existence of the free-of-charge source code at the same time.