MTB Upgrades?
I've had my first mountain bike since January and am looking at bits to upgrade but I'm a bit lost in terms of where to continue, and seeing as it’s a fairly budget bike I don’t want to go spending vast amounts of money on new forks/high-end drive trains etc. as I think it isn’t worth it on such a cheap bike.
I have a Trek 4300 (2014) which only cost me £550 and I use it from everything ranging from cycling my paper round to going on trips to trail centres
So if anyone could give me some ideas for relatively cheap upgrades that I can do (not spending over about £150 on 1 upgrade) I’d be very thankful
My entire bike is stock apart from the following changes which I’ve made:
Handlebars: Crankbrothers Cobalt 1
Grips: Raceface Half Nelson
Saddle: Charge Scoop
Brakes: Shimano XT
thanks and mad props to those who can help 
Comments
You are quite correct that your bike isn't worth upgrading. Unfortunately it seems you have already started.
If you are riding on smooth surfaces your only change (not an upgrade) would be to put narrower and smoother tyres on the bike... that's all.
Attempting to make the bike lighter is not a wise investment and trying to make it "work better" is not a good idea either. If you were planning to sell the bike as you move forward any of the things that you add will NOT make the bike worth more... it is, after all, still a Trek 4300 and all the parts you replace are still needed for the bike to work.
In addition to that, the parts you replaced voided the factory warranty.
Save your money, identify the bike you REALLY want, and buy it.
Bike parts are a lot more expensive when bought piecemeal compared to when bought as a complete bike. An overall upgrade almost never make sense money-wise.
Personal adaptation features, bar, stem, grips, pedals, saddle can make sense to replace. And I'm a big fan of keeping double wheelsets, fitted with different types of tires. But those can (often) transfer to another bike later on, if needed.
Apart from that, the only thing I can recommend is to replace-with-better WHEN something breaks, and not before that.
As Bikeworks points out, upgrading a bike is a tricky business. Unless you have long term plans for your bike, keep it more or less as it came from the factory. Upgrades to a stock bike, unless done with the help of the dealer who sold it to you, void your warranty. They imply that you wish to push your bike beyond its design limits. Besides that, an upgrade means that the component you install will be better than the one it replaces. This is rarely cheap. A few "upgrades" can quickly add up to what a better bike would sell for, and you will lose the whole cost of those upgrades if you attempt to resell your bike to help cover the cost of a better one
Try the Schwalbe Marathon Plus MTB tyres. BMX style pedals are worth doing as well.
If you use it for a paper route I would change the tires to something more road friendly.
i wouldn;t do anything unless something breaks
wle