You don't have to spend any additional money to improve the strength and condition of your nails with commercial preparations.
Infact, your nails and the condition of them can be very helpful in revealing the state of your overall health, as certain nutritional deficiencies will make themselves evident in the state of your nails.
It used to be that my nails were ALWAYS breaking, and the only way to grow them was to keep them constantly polished. The problem with that, is you have to maintain it constantly, and constant use of nail polish, along with the nail polish remover during frequent manicures is that it dries out the nail, making the actual condition of the nail worse. Many commercial preparations make nails so hard that the occasional bump will cause them to break. In that situation, you'd be better off having the nail bend, then flex back into position, rather than breaking.
Now I am able to grow my nails very long without having to constantly keep them polished.
To improve the condition of your nails, look to your diet. If you take supplements, you'll find that by switching from compressed tablets to supplements in gelatin capsules, you'll find your nails improving in strength and durability.
If none of your supps are come in gelatin capsule, another inexpensive alternative is to simply add gelatin to your diet. Knox unflavoured gelatin can be added to protein shakes etc. Or you can simply start eating alot of jello
To improve the condition of your nails, regularly push back your cuticles, and massage the nail beds. Anything the improves blood flow to the fingers will also be helpful.
You should start noticing results in a few months.
ps - Gelatin or jello is not the most suitable if follwing a vegan or vegetarian diet.
Vegetarians should consider regularly supplementing their diets with silica, horsetail etc.
There are a bunch of natural herbs etc that have been traditionally supplemented into the diet to supplement the nutritional components for beneficial optimal fingernail health. Whew I hope that last sentence passes FDA.