Here I will present software which can help you in the lab. It can be software for special molecular biology problems or software which helps you in the office to make documents or to edit pictures. The programms are alternatives to the big well known software bundles your boss thinks you don't need (read: are too expensive).
The software here is at least free to download and preferably open source. So you can use it without asking you boss for money!

Molecular Biology Tools:

If you need to design primers for PCR, this is the best tool for sure. Ok, I programmed it, so I am a little biased. I like it because it is buit on primer3, a widely used program, and it has lots of parameters to set. It may be a little confusing in the beginning, but the better you understand it the more flexible it gets. In short, if you want to design primers, primer3plus will fullfill all your needs.

ApE - A Plasmid Editor
If you need to work sequences, make plasmid maps or look how often a restriction enzyme cuts, ApE is for you. It works well, sometimes a little slow but over all, it's VERY useful and my sequence editor of choise. Unfortunately, the development on ApE seems to have stopped due to legal issues. I still would like to write my own version, but I didn't even start. Untill then, I recomend ApE.

If you need to align sequences, Mega is for you. It allows also to make nice trees and so on. I don't need it very often, so I can't really say what it can do - but if I need to align sequences and make trees it never let me down.

Office Software:

This is a free, open source office package. If you dont know it, try it out. It works very well and it does not cost a cent!

Graphics Software:

GIMP - The GNU Image Manipulation Program GIMP - for Windows
This is probably the best pixel based graphics program. I guess for most people it is all they ever need, the rest has to buy Adobe Photoshop. I had a good impression once I played with it, but I have to admit that I love Photoshop.

This is probably the best vector based graphics program. It is good for drawing schemas and overviews. I think many people use Microsoft Powerpoint for that, but a vector based graphics program is much more suitable. It allows to scale the picture without seeing any pixels when its very big.

Internet Software:

If you need a program to do FTP, this is for you. It can also use SSH for secure connections and it is real GPL open source.