Although there are many armors that cost millions of credits, there’s also a great selection of armors available for as low as 2,500 credits per piece. The Adaptive Vendor, located in the Supplies section of the fleet, sells good looking armor for cheap for all classes. There’s different armor on the Republic and Imperial vendors, and most of the gear is legacy-bound, which means you can transfer it between all your characters on your server. In addition, the vendor also has some very basic weapons for sale.
Here is a map to find the Adaptive vendor on Republic and Imperial side – it is in the Supplies section of the Fleet in one of the little corner cubbies.