@Jason1876
It sounds like you sent a 'request to book'. In that case, the host doesn't have any obligation to accept the booking. Booking someone's airbnb is not the same as booking a hotel room. The host has a say in which bookings they accept or not. If they enable instant booking (and that's optional), then you can go ahead and book without prior approval from the host.
This is all pretty standard. Personally, I have never tried to up the price for dates a guest has already requested. Then again, it's possible that the host meant to raise the price and simply forgot until they received your request. I have no way of knowing really if it was an attempt at 'bait and switch' or a genuine oversight or just an excuse when there was another reason.
If you want to know in more detail the way booking works, it's like this:
1. You can send an enquiry (or inquiry as they say in the US). This is just a way to contact the host and ask them questions if you are not 100% ready to book or are unsure of anything. There is no obligation on either side, the dates are still open for others to book, but the host should respond within 24 hours to keep their rating up. They can also pre-approve your booking, allowing you to go ahead and book if you want to.
2. You can send a booking request, as you did. The host must either accept or decline this within 24 hours if they don't want their response rate to decline, but they may have questions for you before they do. In the meantime, the dates are not technically reserved for you, but no one else can request to book them. They can, however, instant book them, thereby trumping your request.
The host in under no obligation to accept your booking, but most hosts will if they feel okay with it, otherwise they get penalised by their acceptance rate going down, which can affect the listing's position in searches. So, most hosts won't do this lightly.
Once the host accepts, the booking is made. There is often a 48 hour cooling off period (for the guest only), but after that, the cancellation policy applies and there are penalties to the host also if they cancel.
3. You can instant book but, as you mention, not all hosts activate instant booking as it's optional and, even those that do can choose to only accept these types of bookings from guests who have verified ID, previous good reviews etc. if they feel more comfortable doing that.
Once your booking goes through (subject to payment etc.) it's pretty firm but often you also have 48 hours to change your mind. Do always check the cancellation policies on each listing before either requesting to book or instant booking.
Hosts can still cancel an instant booking without penalty, but only up to three times a year and for limited reasons (price changes do not apply to this, but the host could still lie about the reason).
So, for sure, you could use instant book instead if you don't want to go through the whole requesting to book process. Just make sure you familiarise yourself with the listing first, read the house rules and ask any important questions, as you will be entering into a contract once you make the instant booking (bar the 48 hour grace period, if it applies).