there is a sri lankan store at lawrence and midland that makes beautiful garlands… i have to find out the name for you… i cant remember now, but its in a plaza on the south side, i believe…
aman, i think we paid $45 per haar and $15 per gajra. if you have specific colours in mind, i'd order at least two months before, depending on when your wedding is. mine was in august and i ordered the week before and they didnt have any red or yellow flowers left. it worked out though, cos they made mine of pale pink and ivory flowers with a bit of green and silver sparkly bits and it looked really unique and almost hawaiian. so you could take a chance, or you could just order ahead and coordinate with your color scheme.
We used Laila Decor for my sister's mehndi this past September. We found them more affordable than others and the flowers were very pretty. They were also very quick to reply. Highly recommended!