What tools are required?
What to buy? There is radio shack sale going on. While I am still waiting for my onion 2 do I need to buy any tools ? Like a solder iron or something? Please let me know
What tools you need depends on what you are trying to do. In terms of proactive purchases, relatively little of radio shack's inventory compares well with its alternatives, at least not unless deeply discounted. Their soldering irons for example are mostly either primitive or vastly overpriced. Some of their meters are okay, but others take odd, expensive batteries.
That said if you see their wire wrap tool, grab it - wire wrap sockets may be long gone, but it's still useful for making temporary connections to header pins, and will even work with care on 2mm ones like the onion's despite not being intended for that.
Some of the proto boards aren't bad either - you can get deals online but usually only in quantity.
If you see a 1/4 watt resistor assortment at a decent price that can be worth it too.
@Anil-Kulkarni If you don't have a soldering iron and you're asking these kinds of questions, I am going to hazard a guess you're not terribly experienced, and in that case I am offering you some advice: don't choose the cheapest possible iron and don't use lead-free solder. Lead-free has its advantages, yes, but leaded solder is a lot easier to work with, especially if you ain't experienced at soldering.