States have two scanning methods: NFC radio contact with a toll tag in the car, or surveillance photos of the car's license plate. The toll tag takes precedence; they won't try to read the license plate off the photo if the toll tag worked.
I'd rather just pay the rental company surcharges
The car will have its own device, and for 10 days driving the administrative cost will not be too much.
OK then... have fun. There is absolutely nothing to connect you to the toll. The toll agency will attempt to ping the toll tag's transponder. If that fails, they will get the license plate off the surveillance camera. Both of those lead back to the rental car agency, who will cheerfully pay the toll and re-bill you.
Tools place a lien on the title of the vehicle, they don't care who the driver is.
Note that license plate scans take a long time, even a couple months to grind through the system. As such, you can find yourself "dinged" with a small charge (possibly including the $5.95 fee) months later. That is legit.
(from rental agreement) In addition, you will pay all tolls incurred at the maximum prevailing non-discounted or cash rates posted by the toll authority.
There's a micro-ripoff for you. Most agencies charge a discount for toll tag collection, as it is cheaper to administer than license plate entry or cash collectors. For instance, Pennsylvania gives 60% discount on toll tag reads. Keep that in mind when reading tolls.
I'd rather disable the toll tag and pay myself.
You must actively disable the toll tag on the rental car!
You can either kick a fuss at the agency and have them remove it, or trust the flip-up mechanism which places the toll tag inside a Faraday cage. They will hand you the car with the toll tag turned on!
If it is used even once, then you have agreed to their terms for your entire rental. I once rented a car in MDW airport for 3 weeks of business in Michigan (which has no tolls). I went through one toll on the way back to the airport, and threw in coins to the bin. But the tag had already read. This triggered over a $100 charge on my bill (back before the $30 cap).
If you do nothing, the rental car tag will operate preferentially to other payment methods. That is, transponder goes first, and then it fails over to "pay by plate".
Pay by plate
You will have to do this in every state you cross, since I have not found any evidence that pay-by-plate data interchanges across states. And look at the maps closely - Eastern states are not squares or hexagons, and have lots of narrow little "gerrymander" salients where you're in West Virginia for 20km for no apparent reason.
You can set up a payment account for any of the states (i.e. each of the states).
Some people bristle at "yet another account and password to remember". So many states allow quasi-anonymous "no account" setups, where you tell it "this credit card agrees to pay tools for this plate between these dates" (you pick; you can pick 1-2 days prior making yourself responsible for recent tolls, and up to 30 days in the future.) However, since they are "accountless", you cannot revoke it e.g. if the car has a problem and you swap cars. You also are entirely "in the blind", you cannot log in and query the account to make sure everything worked.
(Which is fairly pointless anyway, since converting the surveillance photo into a license plate number takes a couple of days at least. Understand these toll agencies are VERY disorganized, and cannot give you timely answers about license plate scans. But at least with an account, there is something to log into in order to check. The toll tag really works better in this regard.
Is there a way to get a toll tag without high costs?
Man, they make it hard... but Yes.
You will be traveling entirely in EZ-Pass territory. This system interchanges among all participating states. Have an EZ-Pass in one, all will honor your toll tag. (Typically with "tag read" discounts too!)
However, many states have high monthly fees or sell you the transponder, making it too costly for out-of-region travelers.
Pennsylvania is the winner here. They have only a $3 annual fee. Further, the upfront charge of $38 is entirely credited to your account as $35 of toll credit + $3 annual fee.
The toll discounts afforded by your own toll tag more than cover a few years of annual fee. Again, the rental car does not give you those discounts, they pocket them. They rebill you full-boat toll.
You will enter Pennsylvania as you head south from Buffalo. There are several ways to get toll tags or a tagless account. They say if you buy your kit at a 3rd party e.g. Giant or Weis, it can take 1-2 days for the toll tag to fully work. I got my tag directly from a state-run automated kiosk, and it took effect immediately. Try state Welcome Centers if you can find one. (If you buy it inside the Turnpike system, e.g. at a service plaza, the tag did not record your entry obviously. Exit at a human cashier, they will sort it out.)
I can affirm that my Penna. EZ-Pass toll tag works in every EZ-Pass state.