What are the best reliable, cost savings different options of sending money to India?

Cost savings in terms of less wire fees or transaction fees? Since i heard that local banks like TD, RBC etc. though they wire money , charge more than just the wire transfer fees.

Do they accept only CAD or USD as well in Canada for transferring money to India?

Is there any limit on the amount of money which can be transferred ?
Day limit or monthly limit?

How do companies like Western Union operate in such transfers?
Do they take cash or cheques only and/or is there a limit through them?

Are there options like Western Union?

I have sent money to my mom last week thru SBI. Wire transfer $7 flat fee and she got money in two days. They accept both currencies.

I think you have to look at the conversion rate as well and not just the transfer fee ...