The three hard CC items in HoN are Stormspirit, Hellflower, and Kuldra's Sheepstick. I'm also throwing Tablet of Command and Frostfield Plate on this cc list, because while they are not strictly a hard CC it is capable of forcing the other team into some tricky positions, sometimes cutting an entire player out of thier team, making it worth of being called crowd control. Most of these items are going to be seen on an INT hero, or a AGI/STR support hero, such as Behemoth. What this means is that cost is a huge factor in obtaining these items, especially in competitive play, where these are the same types of heroes that are going to be primarily responsible for picking up those all important wards of sight and revelation.
The cheapest crowd control item is Tablet of Command, the force stick, which sits at a measly 2040 gold buying cost, making it easiest to afford of all these items. On top of this one of its components, the major totem sits in the side shop, so when you need a bit of extra hp and staying power in the lane early on you can pick this up relatively easily.
ToC tosses you 6str, 6agi, 16int, and a fun and useful escape movement boost/fight initiation/crowd control force push ability. For such a little amount of gold and such a lot of utility this item is really powerful. However it's often overlooked due to the fact that it isn't a hard CC and there are a lot of other lower cost support items that while they are not CC they bring a lot to the team, such as Nome's Wisdom(2300), Astrolabe(2306), and even Puzzlebox 1(2350). Personally I love this item but I just can't seem to grab it often enough due to other options that just seem to be better spent gold.
The cheapest of the hard crowd control items is Stormspirit, the cyclone stick, sitting at a flat 3000 gold. If we break down the build-up of this item you can see that it breaks up into four pieces that, none of which break the 1000 gold mark, which makes this a relatively simple item to build up. The thing about Stormspirit is that it only has one component out of the side shot(Scarab) making you have to rely on the courier to ferry you some items. Not only that but for an early game CC it's got two medium components in the Manatube and the Neophyte's Book, which means you probably won't be picking this item up until mid game, and even later if you choose to grab a Nome's or an Astrolabe before some CC.
I'm personally a big fan of the cyclonestick for two reasons and I love to hate on it for one. The best thing about cyclone stick is that it lets you chase, making it a great item on a really roaming Thunderbringer, a rocketing Chipper, a ward ganking Pollywog, and a number of other such heroes. To let you chase it gives you both a small movement speed boost of +25 and a 2.5 second blast of whirling wind to let you and your teammates get closer to the target. The second thing that makes this such a great item is it's defensive capabilities. Just got cursed grounded? No problem, just cyclone yourself. The enemy carry is all up in your face, and he has that Shrunken Head activated? Self Cyclone.