Question about what is wrong with my marijuana plant.

My plant is about a month an a half old about 14 1/2 inches tall. FIMMED... and its appearing to show signs of nitrogen deficiencies, burning, possibly bugs. Lower leaves are completely yellow and its slowly moving up. Its also purpleing alot at the top on the stems and leaf stem. Those leaves apear to curl on the edges and slightly blacken.
I am on a very small budget and live in a small town. The stores for nutrients are limited to me. In my area there is a home depot, lowes, and various other expensive stores. I have around 10$ to 17$ to spend on nutrients. This plant is from seed and in the vegatative stage. I am feeding her water and sunlight and i think its now time to give her some nutrients so she doesnt die. If there is any way you guys could help or if i can send some pictures if that will give you a better idea. Please help.
~worried4grower20

Don't quote me on this and some might object. But I have heard of people using tomato food. Where I live I can get a small bottle of a and b food for £2. That's hydro not tomato food.

There are also hydroponic stores where i can find nutrients. Im just worried about prucing and if this plant is even saveable

Go to Home Depot and get a bag of Epsoma Plant Tone. It contains everything a plant needs for healthy growth. You can use it as a top dressing. And can also make teas with it. Great stuff. Don;t give up on your plant. Even if it continues to be a rough grow the knowledge and experience you will gain will help in future growing endeavors.

I also have some clones im working on saving that a friend cut wrong. There are 3/12 clones that i think will live. I wont give up on this plant either i just need to figure out how to save her

Is this the correct stuffhttp://m.homedepot.com/p/Espoma-8-lb-Plant-Tone-All-Purpose-Plant-Food-100047163/202258532