do I have to book a 200.00 excursion or can I get on cable car and go up there and pick what I do? how much is that?
You don't HAVE to buy any package.
It is simply public transport which is part on rails and part hanging from a wire, but just like a bus, you can (I always do) wander up and buy whatever segments interest you at the time. You may find that when you reach Lauterbrunnen that the summit is fogged in and you will have a great and exciting day going no higher than Muerren and Gimmelwald. Or it may be glorious and up you go, buying what you need.
You can see transport fares around the region at http://www.jungfrau.ch/en/tourism/travel-information/tickets-rates/interlaken-ost/fares-for-individual-travellers/ or also summarized in Rick Steves' guidebook chapter for that area. These are all to buy as you go, advance booking not needed or recommended. Swiss Travel Passes or Half Fare Card offer varying coverage or discounts.
Don't know who is trying to sell you this package, but as with all travel you can DIY.
Rick's book has all kinds of info about getting up there, it's not hard at all. And worth the trip!
If you have a railpass it won't cover the cost of the trip but will get you a discount; go into the train station ticket office, either in Interlaken or anywhere else in Switzerland, and they'll sell you what you need.