What is the minimum that one can buy shares in any stock?

You can buy one share of stock at most any broker, however the commission may make the price prohibitive. For example, if you were to buy one share at $20, some brokers have a minimum commission of $30 making the total price $50 for your share. Although you may eventually make a profit the first $30 of upside would be recovering the commission.

There are some discount brokers with less expensive commissions. A do it yourself account is usually the answer. In my opinion the best and easiest is to go to www.capitalone.com360 and open an account. They will let you buy for $4 commission and I might mention they also pay the best rates on savings accounts that I have found with no fees, checking is a great deal too. Check them out and see what you think.

Read this DRIP Primer in Canada
Here is a list of DRIPs in Canada

I used to use Share Builder. The nice thing was that you could buy partial shares. So say you wanted to buy 50 bucks a month of Apple you would pool your monthly with others and buy on a weekly interval. So you might get a tenth of a share but they sorted that out on there end. But they were bought by ING and then Capital One so I got the fuck out pretty fast. The fees used to be a lot more reasonable.

Back when I was in college I would say take a hundred out of my bank account a month and put 50% in Apple, 25% in Level 3 and another 25% in QQQ. Their fee back then was like 4 bucks a month. But I have moved on.

it depends on your share application.. company will allot you :)