Always buy a work of art if you have seen it in person. A photo of a painting is never the same as the original, and the experience with dimensions of the artwork are completely different.
Buy directly from the artist, this saves you 50 % of the price that galleries ask.
Visualize where the painting should be hung take a photo of the interior with the wall (structure) on which the painting should be and if necessary discuss this with the artist or project a photo of the artwork on your wall for a first impression.
The purchase of a painting is often a personal emotional event, do not be influenced by what others think of it, this only makes the assessment diffuse.
You should actually compare the price of a painting with, for example, the cost of a holiday. During a holiday, the experiences are 1 moment, with a painting, the enjoyment can last for years.
Take enough time to make a good decision.