You can start implementing your own.
- Read instruction here
Frappe Cloud - see demo https://demo.erpnext.com/
- create free a/c or buy one instance here ERPNext Pricing 2022
- run test cycle
i) Create your first Customer, Supplier and Item. Add a few more so you get familiar with them
ii) Create Customer Groups, Item Groups, Warehouses, Supplier Groups, so that you can classify your Items.
iii) Complete a standard sales cycle - Lead > Opportunity > Quotation > Sales Order > Delivery Note > Sales Invoice > Payment
(Journal Entry)
iv) Complete a standard purchase cycle - Material Request > Purchase Order > Purchase Receipt > Payment (Journal Entry).
v) Replicate a real life scenario into the system.
Major customization you can do your own like …
a) Adding new fields
b) Adding validations to enter data
c) Adding new print format to print invoices and delivery note.
d) Creating Report
If you need some help in implementing ERPNext you can post job on
http://upwork.com/ or find service provider https://community.erpnext.com/service-providers?country=India
Cost can be vary depending on level of customization and integrations.
You will get some idea here
http://blog.clientsfirst-ax.com/blog-1/-temporary-slug-3c1cb87b-0ca2-44d7-80cd-9394d0699444
Thanks,
Sambhaji