The best way to know what your offer should be is to have your Realtor do a Comparative Market Analysis (CMA) on the property using SOLD comps within a 1 mile radius of the property (the closer, the better) that have SOLD within the last 3 months. This will give you current market value and this is what you should base your offer on - not on tax value or list price.
As Anna notes, the tax assessment has little or no relationship to the actual value of the property. Don't use that as any sort of benchmark.
Have your Realtor (not the listing agent) run the comps on the property. Find out how much it's really worth. It could be $415,000 . . . or $400,000 . . . or $370,000 . . . or less. If it's worth less than $375,000 (which it could be; that's only 6% under the listing price), you actually could end up making your "low" offer and end up paying more than the house is worth.
Again, though, there's no relationship between tax value versus asking price versus true market price.
Once your Realtor gives you the information and an estimate on how much the house is really worth, you'll have a starting point. A ceiling. You certainly can offer less. Just recognize that the lower you go, the longer your odds are of having your offer accepted.
Hope that helps.
As far as an offer, has this agent pulled the same comps and appraiser will? If not, get that done and if they can't, fire them and find one that can. There are no rules so stop trying to handcuff yourself, you're the buyer so take advantage of what you can.
Just an opinion - your agent seems like a dud, it takes maybe 20 minutes to write an offer. If they are this dramatic, put them out of their misery and fire them. It is your money isn't it?
Here's the scoop and this is me thinking outloud...according to county records: FMV 517k / asking 499k / comps i could find (using county available searches) 430~450ish not a lot of data like i mentioned above. Square footage..about $100/sq ft sales...I'd be asking 95$/sq ft... This house now has 4800sq ft. recently completed basement.
Maybe I've watched too much HGTV shows but I want to go in at 450 ~10% below asking(i've heard in some markets 20% below is about the max)... just seems a lot off when it's so much money. I agree with the answers below that I should be able to ask what I want within reason because of the fiduciary concerns a Realtor has to meet but my realtor(not my mom mentioned above) said that this wasn't a fair offer..essentially not taking me seriously enough even start with some paperwork.
The owner built the house and wants to move and that's hard to do over the holidays, houses don't move well until Spring arrives...these factors do weigh on my decision as well because of thoughts they may have more equity in their home than most (i know i did due to building my own) these days and motivation to move may outweigh financial gains possible.
I know everyone wants top dollar for their house just as I did when I sold mine. The reality is I needed to sell because of a move and the first fair offer was done. I just need to know if 450 is fair I guess and hope the comps will tell. I don't want to go down the road of firing a Realtor but looking at some of these responses I can say I'm not real happy right now.
thanks again for your help and professionalism...this is why one should always have a Realtor!
In short - you are the buyer, your offer should reflect current closed comparable homes and the current market....offer what you think is a good number for you. I would strongly suggest consulting an appraiser or experienced agent for a review of the recent closed comps.