At The Teachers' Lounge™ we use 3mil THICK film - that's probably twice as thick as the film at your school.
Our film is 27" wide - which means your items should probably be less than 26" wide to make sure they fit. Have something wider like a map? We've had great luck cutting them in half, laminating each half and then using packaging tape to join them together - you almost can't tell you cut that map in half at all! If you have very long items (over 6' long) the narrower the better.
Except at the busiest times of the year, we can usually laminate your items WHILE YOU WAIT. In late July/early August you often have to leave your items behind and we will laminate them on a first-come-first-served basis. No worries - we'll call you when done and you can come by and pick them up anytime.
We charge $.89/foot of film used (minimum of 1 foot). While our laminator does have a counter, we usually "round down" the measurement to make up for inefficiencies in laminating. That is, suppose you have 10 posters that are 24" square each. We will get those probably 1" apart so it will end up using 21 feet of film (10 posters times 2' plus 1' for the gaps between) and you would be charged for the full 21' of film - no film was wasted.
However, suppose you have many of 3x5 index cards that we place an inch apart while we load the laminator as quickly as possible. In the end, the counter might say we used 20' of film was used but we might determine that really we could have squeezed those into 18' of film had we put them closer together. So you only pay for 18' of film. Our goal is your satisfaction!
To laminate a single piece of paper at The Teachers' Lounge™ will cost you $.89. Likewise, THREE PIECES of 8.5x11 paper will cost you $.89 (three across). For comparison, if you do the math, we charge $.40/sq ft. Check out some other prices in town:
UPS Store: $2.00 3mil
Fast Signs: $4.50/sq ft 3mil
PostNet: $4.00 for up to 12"x18" 3mil, 5mil, or 10mil
Office Max/Office Depot: $1.99 5mil, $2.49 10mil - regularly lamination is $1.99/sq. ft. for 5mil
FedEx/Kinkos: $1.99 5mil, $1.99 10mil - regularly lamination is $3.00/sq. ft. for 10mil
Hi-Tech Copy: $2.00 3mil or 5mil
The Ink Spot: $1.30/sheet 8mil