What lens to use?

[usayit]

I'd think a 35 f/1.4 would be the most versatile.

At that point, I personally prefer the 24mm focal length but Op wanted cheap.

 

[usayit]

if ill be getting 50mm f1.4 should i get an extension tube so i can get a longer focal length?

not extension tube but a teleconverter (canon also calls them extenders). Extension tubes doesn't have any optics and are generally used to shorten min focus distance. Teleconverters can be very convenient but you'll take a hit in IQ and loose a stop or two.

how about other canon compatible lenses like tamron or sigma? is it cheaper with quality?

Some are good some are not.. Can't really talk at the level of brands... discussions on their quality need to be discussed at a specific lens.

 

[Hobbes]

hehe I use EF-S 17-85 f/4-5.6 IS USM lens with my EOS 40D when I take night photos without a tripod. it's a lil bit hard but doable but I think the ideal zoom lens for that would be the EF-S 17-55 f/2.8 IS USM that is if your camera has APS-c sensor.