Its better to get a starter set in terms of keeping costs low, IMO. I suggest keeping an eye on one of the many "deal" sites out there. If you'd like a specific recommendation PM me and I'll send you a link.
You should have some idea what kind of tools you're looking for, though. Metric, standard, Allen, Torx? Size ranges? Specialty needs, for things like the wheel axle or spark plug replacement? Most of those requirements are listed in a bike's service manual and I'd get the basics to start and add on as you do more advanced work. For example, to do some sportbikes' valve adjustments you need feeler gauges. Depending on the type of valves, you might use one of two standard shapes of feeler gauge. Bike-specific forums are your friend if you lack the Service Manual.
Dragging knee is for the track, and dragging tail is for the lot. --Kane Friesen
When you're in a car, you're watching a movie; when you're on a bike, you're in the movie. --Robert Pirsig
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