not an exact number but... here's an old thread on cost to play from a few years back:
https://www.planetcalypsoforum.com/...lay-Entropia&p=2122881&viewfull=1#post2122881
Playing economically can have a major impact on cost to play. How you decide to do that is where it gets tricky. You are right, at the low levels playing free or at a low cost per hour is very boring... As you go higher in levels it gets very grindy and boring in that regard. Also, the cost per click gets higher the higher up you go in levels and challenges... It is possible to play for free, but that is a very, very, very difficult/boring thing to do, and the odds are likely that the cost of internet and electricity to do so will make it not a worthwhile thing for most... but some can and do do it... not easy, but it is possible. If you go the freebie route, expect to hunt a lot of stuff on the ground and sweat for hours on end, only to find that you can't sell the sweat too easily unless you have the right contacts or hours upon hours on hand to spam chat channels.
If you haven't invested a lot yet in either monetary or time resources, and already find it boring as hell, it might be a good idea to exit stage left before you become 'addicted.' For some the learning curve itself is the challenge that makes the game a worthwhile pursuit. As far as the learning curve goes, if you do wish to continue in game, study the in game chats (sign up for major chat channels if you figure out how to do it - Mindark's website is less than useful on that, just as it is for many things), study the forums and history therein - but don't use old outdated info too much as things change majorly over time from year to year, study
http://www.entropiawiki.com/ , study
http://www.candyman.se/pe/bobthebuilder/v2/ if the learning curve still does not entice you, perhaps it is time to get out before you get in over your head. Search youtube and other social media sites for entropia tutorials and stuff. Stay away from any sites that claim to sell you peds outside of the game or offer you get rich schemes with automated bots, macros, etc. Most of those are scams.
On the cost thing, some can get buy on 10-30 bucks a month, but if you do it will limit you a bit on what you can do. The dollar per hour in game estimate does work on some items and some stuff, but is a very low estimate on a lot of other things (although some can figure out how to make it a high estimate if you do figure out the learning curve a lot)
Don't try to be an uber in an hour or a month. If you do you'll likely just run up a credit card bill and become pissed off at the end of the day when you realize how much you dropped in to the deposits. If you enjoy chatting and socializing, playing free or low cost is pretty easy to do. However, many that do that can and do get tempted when "investment opportunities" come knocking that cause them to be very tempted to deposit more, More, MORE...
Just remember to only put in what you can afford to lose. Since the loot pool in game is compared to gambling by many, remember the old advice for real world gamblers, "Bet with your head, not over it."
When comparing this game to others, be aware that there's quite a few planets in the game, and each has their own theme and style of play... so each planet is sort of a mini-game... with pros and cons. Each continent/asteroid/server on each planet also has their own sort of theme with different goals, etc. Just because you don't like one planet you start on doesn't mean you won't love another one... but the travel between the planets will cost you a bit, and space is a pvp zone that you can get looted in... so you have to be careful. Mother ships can help you travel a bit safely, but even they get blown up by pirates from time to time.
Don't carry lootable items in pvp zones if you can help it... but maybe pvp is your thing and that's an entirely different journey you might enjoy in game. Some do, some don't. Most hate pirates, but some love to be pirates and that's all they do.
Remember, all items in game came from somewhere... so at some point in time someone obtained almost every item in game WITHOUT paying a ton of markup to someone else playing the game in order to originally obtain it... with the exception of auctioned items that originated on the auction block without a buyout price. In other words, don't pay a lot in markup for stuff UNLESS it's something you really need, want, or can easily afford. Some markup prices are justified, others not so much. In recent years a lot of markup has lowered vs where it was a couple of years ago, but on other things just the opposite has happened. In general, the newer an item is or the better an item is the higher the markup is going to be, but that's not always the case, and a lot of folks can and do manipulate the auction markup prices trying to get what they own to sell for a lot more than it's worth through selling items on auction to their "brother, mother, cousin, (alts, etc.)" Technically that type of market manipulation is against the eula, but it happens a lot anyways, at least on some items. Some shops in game do sell for less than auction prices, but others sell for more. Some player to player trades are better than prices on auctions or shops, others not-so-much as resellers are out to make some cash for all the hours they spend spamming chat channels...
There is definitely a lot of learning curves in the game, but the question is are you up for getting past those hurdles or not? If not, get out before you get too invested mentally, psychologically, or monetarily.
If nothing else, learn what SIB (skill increase bonus) is and what the difference is between Limited (L) and Unlimited (non-L) items before you proceed too far. There's a lot of items in game that have both L and non-L variations of the same item... and some of them are Sib, some not.