So in a sense, are the deflation and inflation of BTC kind of like stocks?
Since it's effected by current events relating to BTC.
And also it's ran by supply and demand?
The price is linked to future price expectations and supply and demand
Bitcoin is an inflationary currency in the sense that the number of bitcoin is rising : 11m today to 21m in 2140 but the number of users and the wealth it represents is going up faster so the price should appreciate
So if I was to buy btc, would now be the best time?
Since that the price is appreciating right now.
Also 2140 is going to be a really long time from now. Would this investment be worth it?
2140 is just when the last satoshi will be mined.
But, if you look at the schedule, you will see by:
2016 - 3/4 of all btcs will be mined
2020 -7/8 of all btc will be mined
2024 15/16 of all BTC will be mined
I would say inflation after 2016 become very low and after 2020 become inconsequential.
in 2016 inflation will drop to < 4.5%/year
in 2020 inflation will drop to < 2,5% year
in 2024 inflation will drop to < 1,25%/year
The games will be over well before 2140.
Already after 2020 there will be little to be decided.
Trying to pinpoint inflation amounts is impossible because right now Bitcoin's value is really determined by the bilateral currency (i.e. The $US). If QE4 or 5 were to pop up around the corner, that will increase the supply of US$ a lot, making one dolloar worth less and making any fixed supply currency more valuable.... i.e. Bitcoin. Notice how since QE is slowing, Bitcoin's value has pretty much just flattened?
Basing inflation rates on the fundamentals of Bitcoin itself (without accounting for the US$ or the formalized fiat) is insane because Bitcoin hasn't been completely adopted (and won't be) and because it's value is still a function of other currencies.
Bitcoin's price is based on supply (which is fixed), demand (which is a function of both inflation in non-digital currencies and general acceptance and adoption). That's why modeling Bitcoin's price is actually quite possible.