hey guys. what do i need to design a website from scracth, do i need to buy anything

Generally, I do not believe that you have to buy any special software, but of course, there are always some that will help!

If you are a fan of wireframing your site designs (or producing low-fi designs) before putting colour and graphics into your site, I would recommend using a trial of Balsamiq! Treehouse offer an extended 90-day trial instead of the default 30 which is nice too! This is particularly good for working out the structure of your pages and allows you to create very quick but effective mockups of your proposed site design. This is a great step towards helping you understand the goals of the site that you want to build.

After wireframing, I would suggest looking towards the graphical elements of your site. Things like colour schemes, imagery, typography and the like are all key aspects that need to be addressed early into your design.

For colour scheming, I would thoroughly recommend Color from Adobe! This is an excellent way of finding great colour schemes from other user's swatches or creating your own from scratch or by uploading an image or a logo that you want to centre your colours around.

Imagery is an important one. Perhaps stock imagery sites could help you (there are some great royalty free ones out there, Google "unsplash" and "Death to the Stock Photo" to name only two). If you have your own imagery though for the site, even better!

Focussing on your question however with regards to software, I personally find Photoshop, Fireworks and sometime Illustrator very useful tools. I'm not much of a graphic designer, but I find these tools quite useful in different projects, even if it is just for recropping, optimizing or manipulating images. These come with a hefty price tag though. For an open-source and free solution, try GIMP perhaps? I hear it is very close in capability to Photoshop.

That is pretty much all I use for designing sites. I am not much of a designer myself but I do find that these tools make my workload a little lighter and take some of the creative pressures away from me. I always tend to Google other site designs that I like for inspiration and base my design from elements of others. And then once I have a design mapped out, its to the code editor (my preference being Sublime)!

Finally, after considering the previous options, you should never underestimate the value of the good ol' pen and paper!

I hope this helps you in your quest to become a better designer! Good luck!