Unfotunately there's no real equivalent (pricewise) to the very inexpensive Canon 50/1.8
in crop sensor lens. A minimum cost option would be the Canon EF 35/2.0
. It's a full frame lens, so even if you move to full frame at somw point it will still be usable. The Sigma 30/1.4
is the fastest option under $500 - though it's only for crop sensor cameras. Another option is the Canon 28/1.8
which also covers full frame and just sneaks in under $500.
Much depends on whether you like a slightly long or slightly short "normal" lens.
35mm APS-C = 58mm Full Frame
30mm APS-C = 48mm Full Frame
28mm APS-C = 45mm Full Frame
24mm APS-C = 38mm Full frame
"Normal" lenses are usually in the 40-50mm region. Technically a "normal" lens is one with a focal length equal to the diagonal of the frame. For 35mm that's 43mm and for APS-C it would be 27mm.
I often use a Canon 24/2.8
as a "normal" lens on my 40D, but I do tend to prefer a "wide" normal lens.