The problem with that is that the head may not come off so could be a little tricky getting your module inside it, also you would need a diver, as the driver for the 5mW diode would not drive the 100mW red
Another point would be that you would need 4.5v to run the driver & diode so a Lion battery would be needed and a spacer to take up the 2nd AA space.
by the looks of it he was going to swap out the diode for a 100mw, If you want a cheap host, look on the BST section there are a few that sell cheap kits, I don't want to name name because that would be unfair, but you could pick up a host and heatsink for about $15 for the diode if you want cheapness get this New 150mW 650nm Burning Power Red Laser Diode | eBay
I'm running mine at 250mA and burns fine :eg: as for the driver just read around here and you'll find something to suit your needs
Its cheaper then what you linked and can do 180mW-200mW. It comes as a Bare diode with No ribbon on the back like the picture shows. So No worries about getting that off.
Pick up an Aixiz module rather then those DX ones. You will probebly not get it apart. They glue them.
You can Buy one or build one. Since your on a budget You should build one.
If you get the Heatsink from me i will send you some free LM1117 IC's and the correct ohm resistor for the diode i linked for you to build and put together. There are also 2 capacitors that the DataSheet says to add however i have never used them on personal builds and never had an Issue.