That is not how leasing works. Lowest MSRP does not equal lowest lease monthly payment.
Please review the forums and learn how leasing works (how a lease payment is calculated) if you want to save thousands and/or lease a far superior vehicle. I have no idea if $351/mo is reasonable for a Yaris because you haven’t provided any details on how that payment was arrived at.
For reference, people on here are leasing $60k BMW 5-series for less than what you are being quoted on a $16k crapbox.
I need a lease that is the minimum possible length, that is why I am going with 24-month lease over a 36-month lease. I got a quote from a CT dealer that I pay $1139 up-front (which includes doc fee and first month) and then pay 305$/month for the remaining 23 months. Is that a reasonable deal?
Also please keep all your related posts in one thread.
No, you can buy for that much.
Please use a broker, it is probably not in your best interests to negotiate a lease deal alone.
If you want the shortest term and lowest cost, you should be looking at Swapalease or maybe Fair.com.
You can try reaching out to Jim (@Jrouleau426) since he deals in Toyota’s and can tell you if a Yaris or Corolla at 24mos are leasing decently, or you could get a low-cost Kia, Forte or Optima for under $200/mo.
$350 for a Yaris? OMG, you should totally grab that! And make sure you bend over for the salesperson since he hooked you up!
i think this thread should be merged into the worst deals thread. You can do a lot better.
At least this time around the person didn’t come here AFTER signing contract.
Have to give credit for that!
OP - that is a terrible deal. Search forum. There are tons of better deals posted especially for Toyota’s AND 24 months leases. You can get a vastly better car for faction of that payment and due at signing.
…No.
Just no.
A 24 month lease on a loaner BMW 430i might cost you around the same…
With loyalty perhaps. Without it: Expect ~$400
I didn’t even know they still made that car anymore…do you know how much Toyota you can get for $350+ a month!! A Yaris?? Gee that car should be $99 down and $99 a month!!!
Lol…FTFY 
FTFY 0 down $49 a month.
Race to the bottom.
The dealerships talked me into a 2020 Corolla LE 24-month lease instead, because it seemed like the total amount overall would be the same (I think the corolla is a more attractive sell later than the yaris). Now I’m putting 2 dealerships head-to-head. One is asking for $7900 Single-pay lease with taxes, fees, and gap insurance. Another dealer is offering me the same, but with $1139 down + $294/month for 23 months. I believe the monthly payments is the better way to go than the single-pay lease.
Both those options are spending $330-350/mo for a low end commuter car. I guess there’s just no helping some people. 
Did you read and understand any of the feedback in this thread?
You can lead a horse to water …
I do not want a high-end car, I would like a reliable basic safe car that will get me to and from work, and keep my insurance costs down, as well as the costs associated with any fixes. Am I wrong to want a plain toyota then?
Read the message boards and get a broker.
The Leasing 101 section will provide a lot of guidance - https://leasehackr.com/blog?category=Leasing%20101
Hope that helps!