Car rental in Albufeira is offered by several major companies: Avis, Hertz, Europcar, Guerin, Goldcar. You can book a car on their official websites. In Portugal, the right to rent a car is available to tourists who are 21 years old or older (drivers under 24 will be charged an additional fee of up to 20 EUR per day) and have a driving experience of one year or more.
You will be required to show a national driver's license (on plastic), in large companies you will also need a credit card (on it will be blocked the amount of the deposit for car rental in Albufeira). In small rental companies, the deposit can be paid in cash (it is quite decent - 1000-1500 EUR). The cheapest car rental in Albufeira is in local small firms, but the owners of such offices rarely take on insurance obligations.
The price of car rental in Albufeira depends on the term for which the car is rented, class of car, insurance, age of the driver. On average, expect to pay 40-50 EUR (e.g. for a Ford Focus).
But in practice, the real amount of the rental is higher: first, you need to return the car with a full tank of fuel (if you forget, in addition to the cost of gasoline, you will pay an additional 30 EUR fine), and secondly, Portugal has toll roads (about 1 EUR per 10 km). You can pay the toll at toll booths (Portagem) to the operator. So, if you want to make car rental in Albufeira inexpensive, use, like most locals, the free roads.
Standard parking costs from 1 EUR per hour. It's true that there is no free parking in the center of Albufeira, and paid parking lots are already empty at 9:00. Locals often offer to park in their lots for around 5 EUR.
Another tip: try to rent a small car, Albufeira has quite narrow streets and many difficult stretches of road (so you have a better chance of protecting your car from scratches).