Most peoples will answer you the best time to buy altcoins is when the coin price is on the bottom or dips.
If you know this is the bottom price of the coin, buying is the good thing.
But if you still not sure where is the bottom, maybe you can wait and keep observing the market.
Sometime buying in ICO is good, you can get some bonus from it.

Some time ICO is the best time to buy and invest our money, many ICO have higher price more than 100% after listing at the exchange market, but some time we can start after listing at the exchange market.

Actually we can't predict the market and you have to study your own and select the coin then invest... initially you should invest small amount...

I guess the best time to purchase altcoin is in the ICO. Be that as it may, the dangers of getting a token in the ICO can be more noteworthy. Since the token can be trick or may not enter any exchanges which you purchase in the ICO. So in the event that you need to join ICO and purchase token, you ought to complete a decent research. In the event that you state that I can not go out on a limb, I prescribe that you trust that the token will start exchanging on the trades.

If you are very eager to participate in ICO, the best stage to invest is of course in presale stage as their are plenty of bonuses in it compare to ICO stage or once it will reach to any exchange.
Though you can buy the tokens in low once it will arrive in exchange but also you will not receive the privilege to have a bonus to what you have bought.

And please note also that this scenario will apply only to trusted and legit ICO and please bear in mind that there are almost 90% of all ICO that are not legit. So better do your own research in order to join the best ICO. 

yes when the Altcoin price falls, this is the right time to buy because it is likely to rise again. now is the right time if you want to buy, choose a good and convincing Altcoin for the future. if you have bought, some have been invested and some have been saved, if the movement has improved, then you are adding investment and waiting for you to earn a large income.

It depends on the project when it is better to buy its tokens - if it has a top team and many investors and partners, it might be profitable to buy tokens during ICO. Generally, the price of the tokens of the most projects is usually dumped after hitting exchanges, so it is better to buy them on exchanges.

I hope bear market is over and we are entering to the bull market on new year.
Ethereum already started to rise but its related to hard fork.
Bitcoin price is stable around 3500-4000 band and this is really good for a new start.

I think this is the right time you can enter to buy Altcoin when the price is cheap and you sell at an increased price, for me now is also the right time to buy it, because now the price is still low.

the right and best time to buy altcoins is when the market conditions are experiencing a lot of bad news and the condition of the price of bitcoin is also falling, the price of the altcoin is sure to fall and make it the right time to buy as many coins as you can. Take advantage of ico to buy altcoin because surely you will get a bonus of up to more than 20% of purchases of ico.