You could start small then, maybe up to 1kg, then buy bigger ones.
You could try doing some yoga poses for faster results, like the plank pose

which strengthens the whole body simultaneously. Just do it as much as you can last, even if that is a few seconds.

 

Kickbacks (Triceps), French Press (Triceps, my favorite), Power Curls (Biceps), Push-Ups (Whole body / chest) and Sit-Ups (Stomach) are your best bet. Adjust the weight to be able to get around 8 to 10 reps.

If you cannot, then getting there is your first goal.

What's important is to do the exercises correctly - watch some videos that do some explaining.

Building up chest muscles will be nigh impossible with weights and without body exercises assuming you do not have a bench or anything of the sort.

 

Stick with bodyweight exercises for the time being. Do pushups, situps, pullups, etc.

 

First, don't buy dumbells off of amazon. as you get stronger, it will cost you a fortune (in shipping alone!). Buy a gym membership.

If you want tone and strength, lift light weights many times. Start low, and go until you have trouble lifting more than a few pounds (or kg or whatever).

DONT forget about lower body as well. You have to stay rounded. You WILL start to look funny if you only work upper body. Free weight exercise is best, but you can use machines at the gym to get started.

DONT forget cardio (heart is the most important muscle, and as your other muscles grow, it needs to be able to supply more blood!) and flexibility. Always stretch before and after you workout, or you wont get toned, youll get bulky in weird places or worse, hurt yourself.

DIET is 85% of your workout. EAT plenty if you work out, don't starve yourself, you NEED the energy. Just eat HEALTHY

LEARN about all of the different muscles in you body, how they move, and connect. when you learn how to isolate each one individually, you will be able to maximize your workout.

sorry about the caps, it just that I see soooo many people at the gym hurt themselves or work their asses off for no gain everyday, and they get so offended when you try and lend a hand! the fact that youre starting and already asking for help puts you miles ahead of most people who ever start!

get a routine down, you will instantly feel better mentally and physically. within 3-4 weeks you will start to notice a difference in how you look. in a years time at 22% body fat you will look like a super model. don't be too concerned about weight, muscle weighs more.

good luck! PM me if you need any advice besides this. (if you have the money for it take a few classes with a good personal trainer, they will help you in ways nobody can over the internet)

 

For the record, I'm 158cm and 45kg. Female. Age 20. Relatively high body fat (22% the last time it was tested)

22% is not high at all for a woman. Actually it's pretty good, even more considering that you don't exercise.


Anyway, buy a 20kg set of adjustable dumbbells, something like this.
As the poster above me says, it makes more sense to buy a gym membership if you want to save money. If your as weak as you say you are, a set like this should last you quite some time, even more if you go for slower repetitions but it's eventually going to be too little for you, especially for compound exercises.
If you're not sure you want to do weight lifting, you could just follow a routine of bodyweight exercises: there's a subreddit called r/bodyweightfitness which has several fully explained routines. You save money, time and every exercise is adjustable to your level of fitness.

 

Chin-up bar does wonders. I got a portable one that fits on my bathroom door.

 

That's probably too advanced if she can't even lift a suitcase overhead.

 

When you start, you'll make crazy progress for about the first 90 days. Save some time and money... use some old milk jugs and fill them with however much water you need. If you get straonger than that, you could even start filling them with cement.

 

That's a great idea. Come to think of it shipping would be insane for dumbbells. I just asked my friend for his empty gallon orange juice bottles and bought a yoga mat. @g_w Thanks for all the book recommendations! I'm going to start with one of the bodyweight books, I think. I don't really find the time to go to the gym because my school work is insanely busy at the moment. Again, thanks everyone for the tips.

 

Two ideas for you both available on Amazon.
1) You Are Your Own Gym by Marc Lauren. Around $10. No weights, just bodyweight, with pictures.
You Are Your Own Gym: The Bible of Bodyweight Exercises: Mark Lauren, Joshua Clark: 9780345528582: Amazon.com: Books
or
Body By You: The You Are Your Own Gym Guide To Total Women's Fitness
Body by You: The You Are Your Own Gym Guide to Total Women's Fitness: Mark Lauren, Joshua Clark: 9780345528971: Amazon.com: Books

2) If you are going to go to a gym, get the book
The TNT Diet
Men's Health TNT Diet: The Explosive New Plan to Blast Fat, Build Muscle, and Get Healthy in 12 Weeks (Mens Health) [Paperback]: Adam Campbell MS CSCS (Author) Ph.D. Jeff Volek (Author): Amazon.com: Books

This book uses dumbbells, and includes eating plans. I've lost about 40 lbs since June 2012 using this book.
It gives EXACT exercises (how to do them, how many repetitions, how long to rest...the book is GOLD.)

The important things are to
1) lift hard enough that your body has to adapt
2) REST enough, don't overdo it
3) EAT enough so your body can rebuild.

Good luck!

 

Also check out the following YouTube video: