Hi, first of all, welcome back to the hobby!Personally I feel like if you’re gonna get a 3-4ft system after a long time away from the hobby, it would be good to get a brand new setup with a leak warranty. This way you avoid potential mishaps that might happen from getting a secondhand setup. Depending on your budget, a new 3-4ft custom system can cost anywhere between 1.2 and 5k. Of course, if you’re on a budget, you can look for those who have recently decommissioned their setup and some even give their tanks away for free. Be aware though that the quality and condition of secondhand tanks varies a lot depending on how old the tank is, scratch marks, worn-out silicone, rusted hinges and whether it was previously used for fresh or saltwater; the glass thickness and whether there is eurobracing is very important for saltwater tanks. That said, you can save a lot of money this way. I myself took over a worn-out 4x2.5x2.5ft system for free that I refurbished on my own on a budget. The system lasted for about 5years before the sump sprung a leak. Some people have the unfortunate happen to them and even new tanks have a small chance of leaking in less than that time, so it’s still wise to weigh your options. Hope this helps! And all the best Sent from my iPhone using Tapatalk