There are a number of options for testing mesh (or any other upload - objects, textures, scripts etc) without uploading them to Second Life Main Grid, therefore not paying L$. For textures, you can use "local" textures that only you can see and check that they are correct before uploading them. You could download and install Opensim on your computer. Most functions work more-or-less the same and you can try out your mesh objects before uploading them. You can, of course try out mesh objects in the program you made it in. For Clothing items, there are a number of programs that allow you to preview the objects on the basic Second Life Avatar. Then there is the SL Beta Grid. Uploads to the Beta Grid are free, though you can not transfer them to the main grid - it is only for testing. You will find it in the drop down box before you log in. Firestorm still supports Beta Grid Logins, though I can't find the option for Beta Grid on the Linden Viewer. For vehicle testing or buildings, your best options are Opensim or the SL Beta Grid. Most functions are the same in Opensim as SL, so even if Linden Lab stop public access to the Beta Grid in future, you will still have a means to test it out in a SL-like virtual environment. The main thing to remember is that Opensim does NOT support Havoc. Of course, no-one can help you with the cost of uploading ready-to-use uploads, that's something we all have to deal with, whether by camping, working, paypal, using bank details or credit/debit cards. But at least we can test things out without wasting money when they don't fit our requirements.