Resources

Places to Buy Cubes:

TheCubicle - Located in New York with a wide variety of puzzles and frequent sales, endorsed by a large number of cubers including WR holders such as Max Park, Tymon Kolasiński and more. 

SpeedCubeShop - Located in Las Vegas, also has a wide variety of puzzles, also great, endorsed by many cubers, the most prolific being Jperm (Dylan Wang)

Daily Puzzles - Located in Australia, best option for Australians, wide variety as well, endorsed by many Australian cubers 

Cubelelo - Located in India, best option for Indian cubers, offers a decent variety (but not as large as the other cube stores listed above)

Algorithms, Trainers, and Timers:

Jperm.net - Website created by popular YouTuber Jperm. It features some tutorials on how to solve some cubes, some tips and tricks, algorithms sets, and an algorithm trainer. The algorithms sets include basic sets such as Ortega, 2-Look OLL and 2-Look PLL, intermediate sets such as Full OLL, Full PLL and CLL, and more advanced sets such as COLL, Winter Variation, and EG-1. 

Bestsitever.ru - Website featuring a multitude of different useful cubing tools (and some non-cubing things). The main cubing things this website includes is a robust OLL and PLL trainer, a ZBLL trainer, a Rubik's cube mosaic building software, and a tool that can inverse scrambles. 

SpeedCubeDB - A very clean and comprehensive website that has a large number of algorithm sets for 3x3, 2x2, 4x4, 5x5, Square-1, and Megaminx. It also has a built in algorithm trainer. In addition to this, it also has nearly 9,000 reconstructions of top cubers solutions and section with reviews of different cubes. 

Cstimer.net - This is a website that allows you to time your solves and store them in a nice way. It has many different useful tools that help your practice different things and track your times better. It is the most robust speedsolving timer out there. Though, it will require a bit of customization to be able to get the most use out of it. 

CubeDesk - This a relatively new timer that came out and though it isn't as customizable as cstimer, it makes up for it with a plethora of other features. For one, it just looks a lot nicer. It also has a algorithm trainer built into it. But on of the best features it has is that you can 1v1 other cubers. 

CubeTime - This is the best timer for iOS. It has all the basic features you need and works just fine. 

Places for Cubing Tutorials:

Jperm - This YouTube channel is arguably the best YouTube channel to learn anything related to cubing. It has everything from how to solve a Rubik's Cube, a endless number of videos in CFOP, how to get fast at 2x2, how to get fast at big cubes, tutorials on blindfolded solving, solve critiques, cube reviews, and more. 

BrodytheCuber - Brody's YouTube channel has a lot of great tutorials and analysis videos, specifically for 3x3 and 3x3 One Handed. He also has a few great videos on 2x2 and 4x4. 

Z3Cubing - This YouTube channel features a lot of different tutorials. Some of the tutorials are how to solve tutorials, that are simple and easy to follow along with it. Z3Cubing also has tutorials on things related to assembly and disassembly of puzzles, how to tension and lubricate cubes, how to remove logos of cubes, cube notaton, scrambling, and much more. 

Other:

World Cube Association - The WCA is the governing body of Speedcubing and regulates and holds competitions. On their website, you can find all the World Records, rules and regulations, rankings, look at past competition results, sign up for upcoming competitions and more. 

WCA Live - Website where you can find the results of ongoing competitions and competitions that recently occured, but whose results have not yet been added to the main WCA website. 

WCA Forum - A place where cubers discuss the WCA's current state and future. Cubers can also ask questions and suggest new ideas and potential rule changes. 

CubeDB - This is an online tool that you can use to reconstruct your own solves and look at other peoples reconstructions as well. This website also has a feature where it will critique your solves and tell you what you could have done to improve your solution.