See if the seller is ok with you paying to have the rig sent to your rigger for inspection prior to purchase. Get the date of manufacture for everything. Your rigger should be able to tell if the price is accurate. From the photo, you can tell that there is bridle protection, so it is a newish Javelin. Talk to your former instructors and buddy up to your rigger. Also, large rigs tend to sell quickly, so you may have to act quickly. Don't forget an AAD.
First and foremost, what is your current jump experience and what canopy sizes and types have you flown to this point. Along those same lines, what is your height and weight (for fitment and canoopy size evaluation)?
You really need to consult with your instructors as to if this is an appropriate rig for you to be jumping, and then you need to consult with your rigger to arrange for a pre-purchase inspection. As a new jumper, proceeding forward without either or the two is foolish, and could be a waste of money and dangerous (or both).
In terms of 'testing it', if you mean jumping a rig that does not belong to you, that's a problem waiting to happen. Make sure that is it absolutely clear, in writing, that you have permission to jump the rig and who is responsible for what in the event of loss or damage while in the process of jumping the rig. Due to the possible complications invovled, it's unusual for a buyer to actually jump a rig being sold by someone they do not know personally. More often than not, simply trying on the rig for harness fitment, and then having a pre-purchase inspection done will tell you everything you need to know about the rig.
In terms of price, that's a subject best left until after your rigger has done the inspection. Any repairs or updates that need to be made will effect the price. Where the rig was jumped will effect the price (a canopy with 250 summer time jumps in the north east will be like new, and one with 250 jumps in the Arizona desert will be significantly more worn). Finally, the overall condition of the rig will effect the price. See what the rigger says, report those results here and then you can get a price. If you can tell us it's a 2003 Javelin, 2005 PD Sabre2 210, and a 1998 PDR 218, all in 'average' shape, then we can give you idea of the value.
This is definitely a discussion that your local rigger needs to be a part of. That being said, if we break it down this is what I see: $800 for a 10 year old reserve $1500 for a 10 year old Javelin $1500 for a 10 year old Spectre.
Assuming the gear is in the kind of shape the seller says it is in, that still seems a little high... In the ball park but a little high.
If you and your rigger decide that this is the gear for you, make him an offer.
This is probably great gear but there is sooo much gear out there waiting for a new home. Don't get sucked into the idea that this is the only gear for you. There are lots of options. Putting up an ad in the classifieds saying that you are looking for a particular component will bring all kinds of replies. You can build the perfect rig for where you are in your skill level.
In reply to:
Sorry about that I totally forgot to mention that stuff. Everything in the rig was made in 2002 and the seller claims that it only has 100 jumps but who knows about that.