Many services have come and gone over the years I’ve been trading. This is my current favourite, because it’s consistent and regularly updated.
The type of service that may be appropriate for you will depend on your level of experience and the level of trading activity that you think you will be involved in. Some services provide several thousand each month, whilst others manage less than 50 per month. Therefore, it’s quite important that you match your requirements with the right service. Otherwise you will either be inundated with arbs or starved. Either way you’re going to be very frustrated.