This is not a good strategy. Priceline lists minimum bids they will accept for rental cars if you successfully bid for a hotel in most markets. The differences in prices are typically small. Even an upgrade via Priceline is more. I reserved a midsize for $14 per day and then was offered an upgrade to full size for $3 (Hertz) at Priceline. Checking the minimum acceptable bid, full size was only $15 that day. I checked back today and these bids would be accepted (for picking up at BWI for a weekend in March):
Mid-size Car - $15/day Full-size Car - $16/day Sport Utility - $38/day
Compact Car - $14/day Economy Car - $19/day
Why would you upgrade at the counter when Economy actually costs more than any other size car?
Just to clarify,
I didn't bid for a hotel i bid only for a rental car.
I am keeping the car for 24 days ad they accepted a rate of $11 for a compact. I tried up to $17 for a midsize but was refused.
therefore i am hoping that someone at the national counter will let me buy my way for $2-3 a day into a midsize.