You're based in Pretoria, ye?
You can check out Silverton Timber Merchants -
http://www.timbermerchant.co.za/
You can also go to Bensaw Sawmills -
https://www.facebook.com/BensawSawmills/
Silverton has a big selection of woods and they're
reasonably priced. Their wood is dry, mostly, but if you're picking an African wood that they've kiln dried themselves, be prepared for some stress and warpage in the wood. I think they take shortcuts by drying too hot too fast. Their imported woods are great though.
Bensaw has a smaller selection and all hardwoods are still in log form. They can cut it for you but depending on when the log was cut you might need to wait a year or two for the wood to dry. They also have huge piles of reclaimed wood. A lot of it isn't really usable for furniture but if you dig around long enough you'll find some good pieces (bring gloves).
Both places can mill and cut the wood to size for you. Not sure what tools you have but without a planer/thicknesser and table saw it'll be really difficult getting your boards tabletop ready. Unless you're one of those old school hand tool guys.
Rustic looks are challenging to get. Sure, there's plenty of guides on youtube and stuff but most aren't relevant to us because they use products we don't have access to here in SA. I'd advise staying away from the stuff you find at Builders/Chamberlains. Some of the Harlequins stuff is okish but personally I'd avoid it all-together.
Most of the rustic stuff you see on Pintrest is likely weathered oak. I import my finishes but unless you're doing bulk orders it's probably prohibitively expensive. What you can do instead is get new white (not red!) oak and make it look rustic. Silverton actually sells "rustic oak" which is quite a bit cheaper (thinner boards with defects like knots - but that's good, eh?). Kiaat is a nice wood but it's old fashioned now. Outopie kind of furniture you get at these big furniture stores.
Check out Rubio Monocoat for finishes. They have an ammonia based graying agent for oak which gives the weathered look, and they have an "invisible oil" finish which kinda does what the name implies - certainly even less visible than a water based poly/varnish.
You can also take a trip to Hardware Centre in Randburg. They import the Liberon products (high quality stuff) and in that range you can get some darker oak stains that you can then distress and finish with a liming wax.