With an increasing number of people moving on to trading for a living, the brokerage rates have been moving southward making the trading look very attractive. But, for the uninitiated, all that glitters is not gold, as a lot of retail brokers resort to skimming, that is quoting you a higher price while it may be available cheaper or quoting you lower while it may be selling higher. This is done by the brokers to make the brokerage rates sound more attractive. This is more prevalent when quotes are taken over phone.
Also, a retail investor needs to check on the credit worthiness of the broker as a default by the broker can wipe out the entire savings of an investor.
Getting a contract note is a must to resolve any rate difference / account mismatch / any other dispute.
In a nutshell, the odds are loaded against a lay investor. I personally feel that it is better to pay a little higher brokerage to a corporate broker rather than being penny wise pound foolish.