Moving on from CCNP to CCIP, I notice that the Composite BGP + MPLS exams have a fee of $150, is this right? or it cost $300?
The BGP+MPLS has the cost of a single exam. The price varies per country. I recently paid approximately 150 euros (including tax), so I believe $150 is a realistic price in your case.
In my country, other combined exams (CCNA or BSCI+BCMSN) have an increased cost (double-cost or slightly less than double). This is not the case with BGP+MPLS (at least up to now).
I believe single exam options help people focus and organize their studies better. Still, it's up to you to evaluate your knowledge/experience and decide which path is preferred in your case.
In the past when I've paid for a composite exam for Cisco I only paid for 1 exam. Essentially Cisco is saying you have a choice of three different exams: 1) BGP 2) MPLS and 3) Composite BGP + MPLS. It's your choice.
I've seen people take the option of the composite exam only because they were familiar with the material and wanted to get the exam out of the way. On the other hand people who are new to something would rather take things one step at a time.