dimmer a bulb with pwm

hi guys i need to control light of 15 incandescence bulbs indipendently with multiplexer and arduino in forum i've seen various post on this issue, some posts advice for DC Controlled Light Dimmer Kit K8064 there are some videos on the net and seems to be a good, quick and robust solutions. but i need something for 15 bulbs, i need something cheaper then a 30 euro kit for a single bulb.

other solutions?

We need to know the voltage and the current for each bulb. If they are mains powered you can't multiplex them.

40W 230V each. i've used a multiplexer (TLC) with a rele for each bulb. now i want to change relé (only on or off) with a dimmer-triac stuffs (pwm and not only digital)