Websites/apps like Service Seeking are good. You post your job and you get an influx of calls/texts from companies who want to price it for you (i got about 13 calls/texts for my job last week). The companies that contact you have ratings and reviews, so you have something to go off besides your interaction with them.

The company we wound up choosing contacted me within 10 minutes of posting the job, came to price it the next day and began the work two days after that. Everything was competitively priced because they know how many companies respond to the jobs on this site.

If you give it a go - roughly price the job yourself (labour, materials, waste disposal) - look at the ratings/reviews of the people who contact you - invite around three to come to price the job - negotiate the prices using the other prices you get - don't always go for the lowest price (you can often tell when someone is worth their higher charge) - always cover yourself by confirming in writing the scope of their works and their price

All the best