Goatskin is the skin of choice for bodhrans. Cheaper instruments may sometimes have calfskin, whose sound and durability is inferior to that of goatskin.
Tuneable or fixed?
A bodhran skin canbecome tighter or looser sith changes in temperature and humidity. With a fixed-head bodhran, you will need to wet the skin skightly if too tight, and heat it if too loose.
With a tuning system, a bodhran can be tuned without heat or water. This is generally much more practical, especially in a performance situation.
There is a vast variety of different beaters of different shapes and sizes. A longer beater (22-23 cm) is generally easier to play with.
To give an idea of price, you can expect to pay about 50 euros for a fixed-head bodhran, and from around 100 euros for a tuneable. Hand-made bodhrans can start at 100 euros; in general, for 200 euros you will have an excellent instrument.