When first entering the sometimes daunting world that is ebay for the first time, it can help to remember a few things. Personally my rule of thumb is "its better to spend $2 on an item worth $1 that is usefull to you than spending $1 on an item worth $2 that you really dont need". This is especially true during the new ebay user "honeymoon period". i myself and everyone else i know who has used ebay went through the initial period of bidding on trinkets and knick knacks.
from speaking to friends and collegues that use ebay regularly i noticed a similarity in their cases. the majority of these honeymoon purchases were items seen for the first time, i.e. not available in retail stores. things like usb ad ons for computers etc were the most common items purchased. Now by no means am i saying that these items are useless or should not be purchased, heaven knows i'd be lost without my usb coffee cup warmer, but its best to make sure you actually need such things first. a good piece of advice i was given was to add up the total cost of the item (including postage) and think long and hard about what you are about to bid on. I was told to ask myself, "if i was shopping in a retail store would i hand over x amount of dollars for this?"
if the answer to the question is yes then by all means go ahead and bid away. At the end of the day the worst thing that happens is that you burn a little cash and end up with some things that you may not nescessarily need but that are pretty cool nonetheless. just be cautious about needs and wants and you'll have no problem with the ebay impulse and bidders remorse.