amplifier

Hi, I'm toying with the idea of projecting onto my house for Halloween 2019, I would like to also have sound. I'm wondering whether I could have speakers (on low volume) for ToTs and an FM transmitter for people driving by. Firstly, are FM transmitters (for what I want to do) legal in the UK...

is there any type on voice amplifier that can be used in a costume, maybe some thing with a per recorded werewolf growl. with mask on you cant really get the sounds out plus its not realistic

I am looking for an inexpensive amplifier for sound for props and came across this, do you think it is any good? I want to start building props with sound, that can be triggered via prop controllers. I would like to eventually use an Arduino or picaxe or some other type of affordable prop...