In North America, I believe it is common to see advertisements by photo stores to convert a shoe box full of negatives to digital, for about $99. Perhaps that is an option for your locality.
For converting a lot of VHS tapes, hiring a service is probably too costly. Depending on how much quality matters to you, there are a range of options. I've been able to buy enough equipment for <$100 to do it myself, and I even have one of the VCR's this site recommends, plus an extra quality option called a TBC. However, I'll let others respond in more detail. They will probably suggest a quality-minded approach which would require an investment of a few hundred USD.
To put it simply however, you need a VCR and a capture device. You may wish to add to that a device called a TBC as an extra quality option. The status of the tapes themselves make a difference. If they are in very good shape, you will have less trouble getting good results. If they have some problems, the investment in more expensive equipment will give you good results.
There is also the investment of time. You can spend some days learning the process. If there are problem tapes, they will require extra time to learn the skills to give good results. Some people have found this an enjoyable hobby in fact.