it really depends on the studio, and the sub-studio. for example there are three vivid dvd lines -raw, wave, and just plain vivid. raw and wave can be had for $10 - $15. the main line rarely goes below $20 and is usually at $24.
then there are specific titles that cost more -e.g. virtual sex with jenna jameson costs over $30 (i personally wouldn't pay this.)
lately there's been a little more competition so prices are droppping. when i saw that five star had the whole ultimate line (search for the snow leopard $15, elements of desire $17, and the dinner party $15) for so cheap I was happily surprised. this is a great dvd line to get so inexpensively.
in general i would say if it's on sale it's probably an unpopular or lesser quality dvd. but things are changing for our better.
plus as in any online shopping -buy in bulk. at dvd explorer it's buy 4 get 1 free. at five star and divadee you get free shipping on four or more titles. at gamelink the shipping is a flat rate (i think $5) no matter how many titles you buy.
since i'm getting so long-winded here - maybe you should just ask us before you buy

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