Most of the pieces on this site allow you to download perusal copies of the work.
Different categories of music include different subsets of the music in the perusal copy offered:
Perusal copies are intended to give you a feel of the music, but they are not intended to be used for performance.
A perusal copy for choral music will typically include all of the music, minus any extra accompaniment parts that are included.
A perusal copy for other ensemble works will typically include the master score, but not the parts.
A perusal copy for a solo work will typically include a few pages of the music, but not the entire work.
Single page works usually do not offer perusal copies.
Ordering a perusal copy is like ordering a piece of music, except that there is no charge for a perusal copy. If you order a perusal copy at the same time as an order which includes items being purchased, your perusal copy will be emailed to you at the same time as the rest of the order. if you order a perusal copy and your order includes no items of cost, then the perusal copy will be emailed to you immediately.