Old boy is right Memory cards and a spare battery are the most essential, also if you identify what camera bag you want have a look on ebay as peoples equipment grows they tend to sell bags so some bargains can be had.
If you do go for a tripod get a decent one as it will last years if you do, as a stop gap a gorilla pod is good and it is really handy if you have a full sized tripod as well. If you get a tripod then a really nice cheap edition is a hot shoe spirit level, even if your tripos has spirit level they are a lot easier to line up for a nice level horizon.
In general get the basics and see where your photography takes you and get equipment accordingly although it is an expensive journey but a very enjoyable one
