Buying an item from Canada

Can anyone explain to me what is involved in buying an item from a Canadian seller and shipping into the U.S.  The item would be valued at $2500 CAD. What type of duty and taxes will be due?  The item is built in China. Will the shipping take longer than usual?  Thanks for any help. 
Best shipping is via the mail, shouldn’t take too long. If it’s used goods I don’t think there any duty. If new they may be but for most things I’ve bought I’ve never been charged it.   All in all buying and selling across this border is about as easy as dealing in the USA 
I’ve purchased electronics twice w/o any problem. I would advise speaking to the seller by phone first, so that there are no misunderstandings.
If you ship via Canada Post, it will be very slow and the tracking # will be meaningless when it leaves Canada. After clearing customs USPS will transport the item.
UPS is fast; they pickup the item, it gets held in customs for a short time, then UPS continues the delivery. You will be charged a customs fee based on the manufacturer’s country of origin plus the fee to import from Canada to the US. If the seller is a dealer he can give you an estimated fee.

When UPS comes to your door they will charge you the fee as COD (and they want cash).
Today $2500 CAD equals $1968 USD and that gets charged to your credit card or PayPal.
Folkfreak is correct; if the item is from a private seller there shouldn't be any fee. My purchases were from a dealer. For electronics I still recommend using UPS.
I purchased vinyl and CD's no problem thru Canada Poat.
I purchased a 4K preamp from a Audiogoner who lived in Canada. There was no duty tax and it went Canadian Post and then on the the USPS. It took 5 days from Vancouver, Canada to me in New England. I also purchased a CD player from another Gentleman in Canada. It took like 3 days via Canadian Post.  This past Summer, I purchased a new cartridge direct from the Canadian Distributor and I still didn't pay any duty taxes.  It came via UPS and took 4 days.  Easy Peazy.
In my experience, from a private seller, shipping takes double the normal time to go through customs and such.
I purchased a used amp for approx. $2,650 that was made in the US, but I still paid customs clearance fees of approx. $70 and had to fill out paperwork faxed (yes faxed) from US customs.   It was a hassle.  YMMV.
Be careful though, i bought a $1200 CD player from Canada and UPS wanted COD of $295 upon delivery.  I almost paid it but when refused they left a phone number to call, well the next day i called the ups 1-800 # instead and it was explained to me that custom hold fee is only $53 and that delivery person didn’t always have the latest info.  Upon showing payment confirmation # to the same delivery person the very next day, it was released.  SCAM?  Just to add, The second time around the older delivery person brought a ups partner so i couldnt help think it was a body guard.  😏. Did anyone else have this inflated COD charge experience?  
The only way to go is Canada Post. If you use UPS etc. the brokerage fee’s are outrageous. I live in Canada and only buy from the US if it is through the USPS for the same reason.

I have residences in both the Philadelphia, PA and Vancouver, BC suburbs. And I’ve shipped A LOT of audio and personal things back and forth to Canada over the past decade.

First, if at all possible, NEVER, EVER, EVER use UPS!!! They are the absolute WORST shippers between the USA and Canada of any of the typical outfits. They often hold up your shipment in Customs for days, weeks, or in some cases, months. They have the HIGHEST rate of damage your shipment, combined with the WORST record of payout, and the absolute, lead pipe, worst, HIGHEST fees and charges of any of the shippers. I’ve had shipments come in where UPS trickles in fee after fee after fee over the course of several months which left me utterly worn out.

Best way to go is actually same as shipping domestically. For smaller items, use USPS / Canada Post. For larger items, FedEX Ground.

Concerning Customs fees, charges, taxes, etc., Canada is infinitely more on top of this than the USA.  Believe it or not, most of the time, I get stuff delivered to my American residence from other countries, and that's that.  No additional charges, no hangups, no paperwork, nothing.  That NEVER happens in Canada, they always get their cut.

One other thing, if you have a FedEX account, sometimes, there’s not as much difference between FedEX Ground pricing and FedEX Express as you would expect. Of course, Ground is still cheaper, but it sometimes, close enough to make Express the more attractive option. A lot depends on the size and weight of the package itself, but please give it a look. I’ve had situations where my clothes arrived home before I did...
My experience has been that shipping from Canada can be very expensive, usually double what US shipping charges would be.
@trelja ,
As a former UPS employee, I know for a fact that they had/have the highest number of damaged parcels and claims, and the highest fees. Damages are due to the high quota of packages moved per hour.
Can't speak to their service from Canada, except that it was fine for me.

As far as customs fees, Canada seems to be different than other countries delivering to the US. I've purchased many items from UK, Japan, and EU and never paid a fee (VAT). Purchases are from dealers and private sellers.

The cut-off for import into canada, for duties taxes and brokerage fees, is $20cdn. anything over that and you get the whole thing thrown at you.

The same for import into the USA, is $200US. anything valued lower than that just goes through like regular mail.