It depends on the size of course, but you can get a good sized tall 4x4 tent for around $80 on Amazon, or even cheaper if you look for a deal, or a smaller tent. This is an inexpensive tent and it has a 10% off coupon right now:
For 10 or 20 dollars more you can get an even better tent.
I am on a budget also, since I am on disability, but if you start off small and add stuff along the way you will be fine. Luckily, this is the type of hobby that you can keep upgrading or adding to as budget allows.
As far as lights go, if you are the technical type, or know anything about electrical wiring etc, there is a great thread here discussing making your own LED lights for very cheap:
If you want to start off small and arent an electrical tech, yor setup can grow as you get more money. You can always get an LED quantum board on Amazon and buy new ones to add as budget allows. Here is a good one that is only $80, and also has a 10% off coupon (4 of those is ideally what you would want in a 4x4 tent, but you can add them as budget allows, and plants grow):
You will eventually also want to add a carbon filter and vent fan etc., but you can get by in veg, with just one of those LED’s and no carbon filter or vent fan at first, so for around $150 you can get your plants growing in a tent under lights.