No one can tell you how much to offer. If the seller isn't motivated they will not accept the offer anyway. If you really like the home try not to piss off the seller by making a low ball offer. That happened to my seller client and he decided not even work with the buyer who presented a low ball offer.
Have you viewed the home? Is the home presentable? Ask your realtor for comps and see how the home is priced. Homes can stay on the market for quite sometime and for many reasons such as condition of the property, over priced, local market demand etc.
If you are currently not working with a realtor then I'd be happy to assist you. You can call me at 469-371-2899 to discuss.
Realtor & Certified Stager
United Real Estate