The people who usually "B> Astros" are implied to be buying "tradable astros", i.e. tradable items that the seller buys with astros and immediately trades to someone else for ely via the in-game trade system, which is allowed. The buyers aren't usually buying the actual astros or items that require gifting, both of which are indeed bannable.
Although the white tiger seems expensive, its price is far less than the 100m+ it used to cost several months ago. Its 35% (I think it's that much?) crit damage is also better than Gumiho's 22%.
If money is an issue and all you want is the auto-loot, you could also consider a cheaper pet coupon. The golden pig is also available in coupon form and I believe it costs around 20m right now. Sadly, I don't believe a "Gumiho Coupon" has ever been released...
I can understand that making money will be difficult at your level, but not much can be done as long as the economy is dominated by the richest players without generating wealth out of thin air by buying astros. My advice would be try to take advantage of one-time events such as website events or the recent anniversary event that ended last month, join a good guild for moral support (not to mention the occasional crop
), and most importantly, try to live within your means and put everything you've got into getting your level as high as possible even if your equipment is less than perfect. It's a steep hill to climb, but that will just make it all the sweeter when you finally make it to the top.