I am renting a car for the long weekend too so I have already checked the price at different companies. The cheapest one for you at this point will be Enterprise because they have a promotion right now. You pay only 50% for the weekend. An economy car will cost you about $97 including tax for four days (Friday to Tuesday). You need to make the reservation first though.
You should make the reservation ASAP. It is sold out at a lot of the participating locations already.
Please note that the economy cars at Enterprise is very basic. It has no power lock and no cruise control. If you want cruise control, you may want to check out Budget.
The economy cars are usually Hyundai Accent or similar. The compact cars usually has similar price and is Toyota Echo or similar. These cars are definitely weaker than Corolla or Civic etc but driving on the highway is still fine. Rental cars are usually very new and are in good condition.
Enterprise normally offers good price but does not offer unlimited milege. Therefore if you drive far, you may have to pay a lot of extra for the addtional KMs that exceed their limit. Make sure you check it out with them first.