The trick is not to negotiate much on the price of a new bike, secondhand you can usually do far better in this regard.
First off, do your research, who else is selling it in your area and for how much ?
Look around the net and get some prices there, this will give you leverage.
Next off, you need to remember the cost of servicing and kit.
The Nighthawk 750 is very good on servicing costs as it has hydraulic tappets which self adjust, this makes quite a differance.
Be careful about tying yourself down to servicing from one particular dealer, some will offer you a reduced rate of servicing provided you pay in advance, but this then takes away your choice and commits you, when you may not know much about the standards of that particualr dealer, and it ain’t unknown for even large dealer chains to go down owing lots customers their pre-paid services.
Perhaps one of the best ways to save money is to get good kit thrown in with the deal, remember that the dealer is paying trade for it, so he can pass it to you at bery much reduced rates and still be in front.You can do even better if you try to pick out stock that is either not moving, or is last years models.
If you do this right you will get high quality kit for the price of the lower quality, do not buy kit on the basis of saving money, save up and get the real thing.
I’d look to get boots two pairs (one pair would be like heavy workboots and will be ok to walk around in, and the other pair would be longer, offer more protection but also more dedicated to biking), couple of pairs of gloves(light and heavy), one decent set of zip-together leathers, one piece jobs are not versatlie enough, at least one crash hat - maybe another for a partner, some sort of rainproof top, maybe even synthetic jackets made from cordura or the like.
Next, you can do deals on accessories, on a bike like that I’d have wrap around crash bars, not the little single loop ones, I’d have heated bar grips, I’d have a flyscreen, I’d have a luggage rack and box to fit, and I would have a very very strong chain and lock(cheap is definately not a good idea in this matter).
The lock and chain can then live in your top box for ready use, too many riders risk death and serious injury by carrying heavy chains across their bodies whilst riding, and on a long hot day its just bloody uncomfortable.
I’d also think about getting an automated chain oiler device fitted, such as Scottoiler, you will be amazed at how much longer your chain and sprockets will last, and since these are expensive items when you add in the labour costs it makes sense to maximise their life.
On an slightly differant note, do not try to save ten bucks on a chain, go for the best like a DID or somesuch, cheaper chains wear out dispoportionally fast.