Equipment costs for a beginner can vary. There are some items you should own, some you can get away with renting.
To own:
1 Mask: $100
2/Fins: $125
3/Snorkel: $40
4/ Regs: It’s best to own these, you know their service record then $300-$900
5/ Dive knife:$60

To rent:
1/BC ( you really ought to purchase though, $500 new)
2/Lead (to buy if using a 7mm wetsuit $30-$60 depending on if it’s bagged or solid)
3/Wetsuit (personal choice here, buy is $500 for a good 7mm plus booties and gloves $40/pair, hood $30)
4/Dive computer: (optional, to own they start at $300 for a simple model)
5/ Floating Dive flag, to own $30
6/Air tank-comes with a fill if you rent. To own $200 new)

Over the course of perhaps 20 dives or so, it becomes cheaper to own most of that gear. Rentals for a weekend for just the basics can be around $100 or more, depending on what articles you don’t currently own.