The venues you are going to tackle is one of the aspects of carp fishing that you need to think about before you buy any equipment. Large and snaggy waters that require long casts will need stronger rods and bigger reels than the smaller venues. You may also need marker and spod rods, but these are not always necessary.
Bite alarms are also necessary when carp fishing. These vary from very basic models that cost less than 10 to the very expensive ones that cost well over 100. I would recommend getting a receiver when buying alarms especially if you plan on night fishing. Also low quality alarms tend to be less resistant to rain so it is recommend to buy fairly good ones.
Online forums are very useful in deciding what carp fishing tackle to buy. The anglers on there are usually unbiased and helpful. You can get the opinions of many different anglers on tackle. Magazine reviews can often be biased to certain manufacturers and so must be viewed carefully.
When you are ready to buy your carp fishing equipment you can buy online or at a tackle shop. It is better to visit tackle shops as you can get a feel for the tackle and compare many different types. The people working in the tackle shops are usually very helpful and will advise you what to buy. Buying online can often work out cheaper though, but I'd recommend a local tackle shop.
As well as a rod and reel there are a few other bits that you will need to buy in order to carp fish. One of them is a large landing net, preferably around 42 inches. An unhooking mat is also needed as well as bite alarms and carp bivvies if you plan night fishing (many fisheries do not allow colored camping tents).