Between 30-50%; it depends, nation-by-nation (the UK takes 50%).
DVD sales: retailers take around 50% of the price consumers pay.
TV: 100% of the sale goes to the seller (usually the distributor with selling rights in that particular region).
Distributors: for independent films, distributors firstly reclaim all adertising costs before the producer/s see a penny, this is why it's best to get a healthy advance from the distributor (falsely recognised as a "sale"). NOTE: always get a maximum spending cap in the contract or distributors can legally claim that the film made a loss; if a distributor cites a $1m advertising maximum spend in the contract, strike off that first $1m if you're a producr because you won't see any of it - distributors may (not saying all will, but still...) show spending receipts equalling $1m even if that much has not been spent on your film (not even including staff wages).
After all expenses have been covered, the distributor usually shares profit with the producer/s @ 50%.
Total:
Film costs $1m to make
Distributor "buys" film @ $1m (producer breaks even)
Advertising max' spend @ $1m
Cinema sales = $3m
DVD sales = $500,000
Other sales (i.e. cable, airlines, TV, on-demand, etc.) = $1m
$3 / 2 = 1.5
+ 0.5m / 2 = 0.25
+ 1
$2.75m
- $1m advance from distributor
- $1m advertising
0.75 / 2 (with distributor)
Producer's profit (using the above mentioned details of $1m to make + $1m advance to break even) = 375,000
From this point on, investors need to be take profit share and producer/s need to pay actors+crew according to their "points"... it gets tricky from here on in, so it's best that the producer gets a healthy figure up front for producing the film, so that he/she's been paid already and doesn't have to survive on whatever remains from the profits.
Anyway, that's how independent films tend to work - I honestly can't speak about big Hollywood studios with their own distribution arms, but I hope that this gives you a better understanding.